1
|
Ozga M, Zielony E, Wierzbicka A, Wolska A, Klepka M, Godlewski M, Kowalski BJ, Witkowski BS. Effect of repeating hydrothermal growth processes and rapid thermal annealing on CuO thin film properties. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2024; 15:743-754. [PMID: 38952414 PMCID: PMC11216088 DOI: 10.3762/bjnano.15.62] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 06/10/2024] [Indexed: 07/03/2024]
Abstract
This paper presents an investigation into the influence of repeating cycles of hydrothermal growth processes and rapid thermal annealing (HT+RTA) on the properties of CuO thin films. An innovative hydrothermal method ensures homogeneous single-phase films initially. However, their electrical instability and susceptibility to cracking under the influence of temperature have posed a challenge to their utilization in electronic devices. To address this limitation, the HT+RTA procedure has been developed, which effectively eliminated the issue. Comprehensive surface analysis confirmed the procedure's ability to yield continuous films in which the content of organic compounds responsible for the formation of cracks significantly decreases. Structural analysis underscored the achieved improvements in the crystalline quality of the films. The implementation of the HT+RTA procedure significantly enhances the potential of CuO films for electronic applications. Key findings from Kelvin probe force microscopy analysis demonstrate the possibility of modulating the work function of the material. In addition, scanning capacitance microscopy measurements provided information on the changes in the local carrier concentration with each repetition. These studies indicate the increased usefulness of CuO thin films obtained from the HT+RTA procedure, which expands the possibilities of their applications in electronic devices.
Collapse
Affiliation(s)
- Monika Ozga
- Institute of Physics of the Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668, Warsaw, Poland
| | - Eunika Zielony
- Department of Experimental Physics, Wroclaw University of Science and Technology, Wybrzeze Wyspiańskiego 27, 50–370 Wroclaw, Poland
| | - Aleksandra Wierzbicka
- Institute of Physics of the Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668, Warsaw, Poland
| | - Anna Wolska
- Institute of Physics of the Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668, Warsaw, Poland
| | - Marcin Klepka
- Institute of Physics of the Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668, Warsaw, Poland
| | - Marek Godlewski
- Institute of Physics of the Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668, Warsaw, Poland
| | - Bogdan J Kowalski
- Institute of Physics of the Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668, Warsaw, Poland
| | - Bartłomiej S Witkowski
- Institute of Physics of the Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668, Warsaw, Poland
| |
Collapse
|
2
|
Mondal S, Jayalekshmi UJ, Singh S, Mukherjee RK, Shukla AK. Design, development, and performance of a versatile graphene epitaxy system for the growth of epitaxial graphene on SiC. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:063901. [PMID: 38829214 DOI: 10.1063/5.0194852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 05/15/2024] [Indexed: 06/05/2024]
Abstract
A versatile graphene epitaxy (GrapE) furnace has been designed and fabricated for the growth of epitaxial graphene (EG) on silicon carbide (SiC) in diverse growth environments ranging from high vacuum to atmospheric argon pressure. Radio-frequency induction enables heating capabilities up to 2000 °C, with controlled heating ramp rates achievable up to 200 °C/s. The details of critical design aspects and temperature characteristics of the GrapE system are discussed. The GrapE system, being automated, has enabled the growth of high-quality EG monolayers and turbostratic EG on SiC using diverse methodologies, such as confinement-controlled sublimation (CCS), open configuration, polymer-assisted CCS, and rapid thermal annealing. This showcases the versatility of the GrapE system in EG growth. Comprehensive characterizations involving atomic force microscopy, Raman spectroscopy, and low-energy electron diffraction techniques were employed to validate the quality of the produced EG.
Collapse
Affiliation(s)
- S Mondal
- CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - U J Jayalekshmi
- CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - S Singh
- CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
| | - R K Mukherjee
- CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - A K Shukla
- CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| |
Collapse
|
3
|
Ballestas K, Milić JV, Ramírez D. Interfacial host-guest complexation for inverted perovskite solar cells. J Chem Phys 2024; 160:204712. [PMID: 38818896 DOI: 10.1063/5.0202163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 05/06/2024] [Indexed: 06/01/2024] Open
Abstract
Perovskite solar cells have demonstrated exceptional development over the past decade, but their stability remains a challenge toward the application of this technology. Several strategies have been used to address this, and the use of host-guest complexation has recently attracted more interest. However, this approach has primarily been exploited in conventional perovskite solar cells based on n-i-p architectures, while its use in inverted p-i-n devices remains unexplored. Herein, we employ representative crown ether, dibenzo-24-crown-8, for interfacial host-guest complexation in inverted perovskite solar cells based on methylammonium and methylammonium-free formamidinium-cesium halide perovskite compositions. Upon post-treatment of the perovskite films, we observed nanostructures on the surface that were associated with the reduced amount of trap states at the interface with the electron transport layer. As a result, we demonstrate improved efficiencies and operational stabilities following ISOS-D-2I and ISOS-L-2I protocols, demonstrating the viability of this approach to advance device stability.
Collapse
Affiliation(s)
- Kevin Ballestas
- Centro de Investigación, Innovación y Desarrollo de Materiales (CIDEMAT), Faculty of Engineering, Universidad de Antioquia, Calle 70 #52-21, Medellín, Colombia
| | - Jovana V Milić
- Adolphe Merkle Institute, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Daniel Ramírez
- Centro de Investigación, Innovación y Desarrollo de Materiales (CIDEMAT), Faculty of Engineering, Universidad de Antioquia, Calle 70 #52-21, Medellín, Colombia
| |
Collapse
|
4
|
Barman S, Pal A, Mukherjee A, Paul S, Datta A, Ghosh S. Supramolecular Organic Ferroelectric Materials from Donor-Acceptor Systems. Chemistry 2024; 30:e202303120. [PMID: 37941296 DOI: 10.1002/chem.202303120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/04/2023] [Accepted: 11/06/2023] [Indexed: 11/10/2023]
Abstract
Organic ferroelectric (FE) materials, though known for more than a century, are yet to reach close to the benchmark of inorganic or hybrid materials in terms of the magnitude of polarization. Amongst the different classes of organic systems, donor (D)-acceptor (A) charge-transfer (CT) complexes are recognized as promising for ferroelectricity owing to their neutral-to-ionic phase transition at low temperature. This review presents an overview of different supramolecular D-A systems that have been explored for FE phase transitions. The discussion begins with a general introduction of ferroelectricity and its different associated parameters. Then it moves on to show early examples of CT cocrystals that have shown FE properties at sub-ambient temperature. Subsequently, recent developments in the field of room temperature (RT) ferroelectricity, exhibited by H-bond-stabilized lock-arm supramolecular-ordering (LASO) in D-A co-crystals or other FE CT-crystals devoid of neutral-ionic phase transition are discussed. Then the discussion moves on to emerging reports on other D-A soft materials such as gel and foldable polymers; finally it shows very recent developments in ferroelectricity in supramolecular assemblies of single-component dipolar or ambipolar π-systems, exhibiting intra-molecular charge transfer. The effects of structural nuances such as H-bonding, balanced charge transfer and chirality on the observed ferroelectricity is described with the available examples. Finally, piezoelectricity in recently reported ambipolar ADA-type systems are discussed to highlight the future potential of these soft materials in micropower energy harvesting.
Collapse
Affiliation(s)
- Shubhankar Barman
- School of Applied and Interdisciplinary Sciences, Indian Association for Cultivation of Science, 2 A and 2B Raja S. C. Mullick Road, 700032, Kolkata, India
| | - Aritri Pal
- School of Applied and Interdisciplinary Sciences, Indian Association for Cultivation of Science, 2 A and 2B Raja S. C. Mullick Road, 700032, Kolkata, India
| | - Anurag Mukherjee
- School of Applied and Interdisciplinary Sciences, Indian Association for Cultivation of Science, 2 A and 2B Raja S. C. Mullick Road, 700032, Kolkata, India
| | - Swadesh Paul
- School of Applied and Interdisciplinary Sciences, Indian Association for Cultivation of Science, 2 A and 2B Raja S. C. Mullick Road, 700032, Kolkata, India
| | - Anuja Datta
- School of Applied and Interdisciplinary Sciences, Indian Association for Cultivation of Science, 2 A and 2B Raja S. C. Mullick Road, 700032, Kolkata, India
- Technical Research Center, Indian Association for Cultivation of Science, 2 A and 2B Raja S. C. Mullick Road, 700032, Kolkata, India
| | - Suhrit Ghosh
- School of Applied and Interdisciplinary Sciences, Indian Association for Cultivation of Science, 2 A and 2B Raja S. C. Mullick Road, 700032, Kolkata, India
- Technical Research Center, Indian Association for Cultivation of Science, 2 A and 2B Raja S. C. Mullick Road, 700032, Kolkata, India
| |
Collapse
|
5
|
Hatta FF, Mohammad Haniff MAS, Ambri Mohamed M. Enhanced-Performance Triboelectric Nanogenerator Based on Polydimethylsiloxane/Barium Titanate/Graphene Quantum Dot Nanocomposites for Energy Harvesting. ACS OMEGA 2024; 9:5608-5615. [PMID: 38343971 PMCID: PMC10851232 DOI: 10.1021/acsomega.3c07952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/21/2023] [Accepted: 12/27/2023] [Indexed: 04/16/2024]
Abstract
Triboelectric nanogenerators (TENGs) have been developed as promising energy-harvesting devices to effectively convert mechanical energy into electricity. TENGs use either organic or inorganic materials to initiate the triboelectrification process, followed by charge separation. In this study, a high-performance composite-based triboelectric nanogenerator (CTENG) device was fabricated, comprising polydimethylsiloxane (PDMS) as a polymeric matrix, barium titanite (BTO) nanopowders as dielectric fillers, and graphene quantum dots (GQDs) as conductive media. The PDMS/BTO/GQD composite film was prepared with GQDs doped into the mixture of PDMS/BTO and mechanically stirred. The composition of the GQD varied from 0 to 40 wt %. The composite was spin-coated onto flexible ITO on a PET sheet and dried in an oven at 80 °C for 24 h. The output performance of TENGs is enhanced by the increased concentration of 30 wt % GQD, which is 2 times higher than nanocomposite films without GQD. The PDMS/BTO/G30 TENG film depicted an increase in open-circuit voltage output (VOC), short-circuit current output (ISC), and power density reaching ∼310.0 V, ∼23.0 μA, and 1.6 W/m2, respectively. The simple and scalable process for the PDMS/BTO/GQD TENGs would benefit as a sustainable energy-harvesting system in small electronic devices.
Collapse
Affiliation(s)
- Faizatul Farah Hatta
- Centre
of Foundation Studies, Universiti Teknologi
MARA, Cawangan Selangor, Kampus Dengkil, 43800 Dengkil, Selangor, Malaysia
| | | | - Mohd Ambri Mohamed
- Institute
of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| |
Collapse
|
6
|
Ishida N, Mano T. Quantitative characterization of built-in potential profile across GaAs p-n junctions using Kelvin probe force microscopy with qPlus sensor AFM. NANOTECHNOLOGY 2023; 35:065708. [PMID: 37944481 DOI: 10.1088/1361-6528/ad0b5e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/09/2023] [Indexed: 11/12/2023]
Abstract
The electrostatic potential distribution in materials and devices plays an important role in controlling the behaviors of charge carriers. Kelvin probe force microscopy (KPFM) is a powerful technique for measuring the surface potential at a high spatial resolution. However, the measured surface potential often deviates from the potential deep in the bulk owing to certain factors. Here, we performed KPFM measurements across the p-n junction, in which such factors were eliminated as much as possible by selecting the sample, force sensor, and measurement mode. The measured surface potential distribution agrees well with the line shape of the simulated bulk potential. Our results demonstrate that KPFM is capable of quantitatively characterizing potential distributions whose changes occur on the order of 10 nm.
Collapse
Affiliation(s)
- Nobuyuki Ishida
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - Takaaki Mano
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| |
Collapse
|
7
|
Biglarbeigi P, Morelli A, Pauly S, Yu Z, Jiang W, Sharma S, Finlay D, Kumar A, Soin N, Payam AF. Unraveling Spatiotemporal Transient Dynamics at the Nanoscale via Wavelet Transform-Based Kelvin Probe Force Microscopy. ACS NANO 2023; 17:21506-21517. [PMID: 37877266 PMCID: PMC10655243 DOI: 10.1021/acsnano.3c06488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/11/2023] [Indexed: 10/26/2023]
Abstract
Mechanistic probing of surface potential changes arising from dynamic charge transport is the key to understanding and engineering increasingly complex nanoscale materials and devices. Spatiotemporal averaging in conventional heterodyne detection-based Kelvin probe force microscopy (KPFM) inherently limits its time resolution, causing an irretrievable loss of transient response and higher-order harmonics. Addressing this, we report a wavelet transform (WT)-based methodology capable of quantifying the sub-ms charge dynamics and probing the elusive transient response. The feedback-free, open-loop wavelet transform KPFM (OL-WT-KPFM) technique harnesses the WT's ability to simultaneously extract spatial and temporal information from the photodetector signal to provide a dynamic mapping of surface potential, capacitance gradient, and dielectric constant at a temporal resolution 3 orders of magnitude higher than the lock-in time constant. We further demonstrate the method's applicability to explore the surface-photovoltage-induced sub-ms hole-diffusion transient in bismuth oxyiodide semiconductor. The OL-WT-KPFM concept is readily applicable to commercial systems and can provide the underlying basis for the real-time analysis of transient electronic and electrochemical properties.
Collapse
Affiliation(s)
- Pardis Biglarbeigi
- Nanotechnology
and Integrated Bio-Engineering Centre (NIBEC), School of Engineering, Ulster University, York Street, Belfast BT15 1AP, Co. Antrim, Northern
Ireland, United Kingdom
- School
of Science and Engineering, University of
Dundee, Nethergate, Dundee, DD1 4NH, Scotland, United Kingdom
| | - Alessio Morelli
- Nanotechnology
and Integrated Bio-Engineering Centre (NIBEC), School of Engineering, Ulster University, York Street, Belfast BT15 1AP, Co. Antrim, Northern
Ireland, United Kingdom
| | - Serene Pauly
- School
of Mathematics and Physics, Queen’s
University Belfast, University Road, Belfast BT7 1NN, Northern Ireland, United Kingdom
| | - Zidong Yu
- Institute
for Materials Research and Innovation (IMRI), University of Bolton, Deane Road, Bolton BL3
5AB, United Kingdom
| | - Wenjun Jiang
- College
of Transportation Engineering, Dalian Maritime
University, Dalian 116026, China
| | - Surbhi Sharma
- Centre
for New Energy Transition Research Technologies (CfNETR), Federation University Australia, Gippsland Campus, Churchill, Victoria 3810, Australia
| | - Dewar Finlay
- Nanotechnology
and Integrated Bio-Engineering Centre (NIBEC), School of Engineering, Ulster University, York Street, Belfast BT15 1AP, Co. Antrim, Northern
Ireland, United Kingdom
| | - Amit Kumar
- School
of Mathematics and Physics, Queen’s
University Belfast, University Road, Belfast BT7 1NN, Northern Ireland, United Kingdom
| | - Navneet Soin
- Nanotechnology
and Integrated Bio-Engineering Centre (NIBEC), School of Engineering, Ulster University, York Street, Belfast BT15 1AP, Co. Antrim, Northern
Ireland, United Kingdom
- School of
Science, Computing and Engineering Technologies, Swinburne University of Technology,
P.O. Box 218, Hawthorn Victoria 3122, Australia
| | - Amir Farokh Payam
- Nanotechnology
and Integrated Bio-Engineering Centre (NIBEC), School of Engineering, Ulster University, York Street, Belfast BT15 1AP, Co. Antrim, Northern
Ireland, United Kingdom
| |
Collapse
|
8
|
Musa I, Qamhieh N, Mahmoud ST. Ag Nanocluster Production through DC Magnetron Sputtering and Inert Gas Condensation: A Study of Structural, Kelvin Probe Force Microscopy, and Optical Properties. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2758. [PMID: 37887909 PMCID: PMC10609199 DOI: 10.3390/nano13202758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/06/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023]
Abstract
Silver nanoclusters are valuable for a variety of applications. A combination of direct current (DC) magnetron sputtering and inert gas condensation methods, employed within an ultra-high vacuum (UHV) system, was used to generate Ag nanoclusters with an average size of 4 nm. Various analytical techniques, including Scanning Probe Microscopy (SPM), X-ray Diffraction (XRD), Kelvin Probe Force Microscopy (KPFM), UV-visible absorption, and Photoluminescence, were employed to characterize the produced Ag nanoclusters. AFM topographic imaging revealed spherical nanoparticles with sizes ranging from 3 to 6 nm, corroborating data from a quadrupole mass filter (QMF). The XRD analysis verified the simple cubic structure of the Ag nanoclusters. The surface potential was assessed using KPFM, from which the work function was calculated with a reference highly ordered pyrolytic graphite (HOPG). The UV-visible absorption spectra displayed peaks within the 350-750 nm wavelength range, with a strong absorption feature at 475 nm. Additionally, lower excitation wavelengths resulted in a sharp peak emission at 370 nm, which became weaker and broader when higher excitation wavelengths were used.
Collapse
Affiliation(s)
- Ishaq Musa
- Department of Physics, Palestine Technical University-Kadoorie, Tulkarem P.O. Box 7, Palestine
| | - Naser Qamhieh
- Department of Physics, UAE University, Al-Ain P.O. Box 15551, United Arab Emirates;
| | - Saleh T. Mahmoud
- Department of Physics, UAE University, Al-Ain P.O. Box 15551, United Arab Emirates;
| |
Collapse
|
9
|
Gu S, Liu W, Mi S, Xian G, Guo J, Pang F, Chen S, Yang H, Gao HJ, Cheng Z. Twist angle-dependent work functions in CVD-grown twisted bilayer graphene probed by Kelvin probe force microscopy. NANOSCALE 2023; 15:5825-5833. [PMID: 36857709 DOI: 10.1039/d2nr07242d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Tailoring the interlayer twist angle of bilayer graphene (BLG) significantly affects its electronic properties, including its superconductivity, topological transitions, ferromagnetic states, and correlated insulating states. These exotic electronic properties are sensitive to the work functions of BLG samples. In this study, the twist angle-dependent work functions of chemical vapour deposition-grown twisted bilayer graphene (tBLG) were investigated in detail using Kelvin probe force microscopy (KPFM) in combination with Raman spectroscopy. The thickness-dependent surface potentials of Bernal-stacked multilayer graphene were measured. It is found that with the increase in the number of layers, the work function decreases and tends to saturate. Bernal-stacked BLG and tBLG were determined via KPFM due to their twist angle-specific surface potentials. The detailed relationship between the twist angle and surface potential was determined via in situ KPFM and Raman spectral measurements. With the increase in the twist angle, the work function of tBLG will increase rapidly and then increase slowly when it is greater than 5°. The thermal stability of tBLG was investigated through a controlled annealing process. tBLG will become Bernal-stacked BLG after annealing at 350 °C. Our work provides the twist angle-dependent surface potentials of tBLG and provides the relevant conditions for the stability of the twist angle, which lays the foundation for further exploration of its twist angle-dependent electronic properties.
Collapse
Affiliation(s)
- Shangzhi Gu
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China.
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.
| | - Wenyu Liu
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China.
| | - Shuo Mi
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China.
| | - Guoyu Xian
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.
| | - Jiangfeng Guo
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China.
| | - Fei Pang
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China.
| | - Shanshan Chen
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China.
| | - Haitao Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.
| | - Hong-Jun Gao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.
| | - Zhihai Cheng
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China.
| |
Collapse
|
10
|
Moshrefi R, Ryan K, Connors EP, Walsh JC, Merschrod E, Bodwell GJ, Stockmann TJ. Electrosynthesis of Au nanocluster embedded conductive polymer films at soft interfaces using dithiafulvenyl-functionalized pyrene. NANOSCALE 2023; 15:5834-5842. [PMID: 36861258 DOI: 10.1039/d2nr06519c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Nanoparticle (NP) embedded conductive polymer films are desirable platforms for electrocatalysis as well as biomedical and analytical applications. Increased catalytic and analytical performance is accompanied by concomitant decreases in NP size. Herein, highly reproducible electrogeneration of low dispersity Au nanocluster embedded ultra-thin (∼2 nm) conductive polymer films at a micro liquid|liquid interface is demonstrated. Confinement at a micropipette tip facilitates a heterogeneous electron transfer process across the interface between two immiscible electrolyte solutions (ITIES), between KAuCl4(aq) and a dithiafulvenyl-substituted pyrene monomer, 4,5-didecoxy-1,8-bis(dithiafulven-6-yl)pyrene (bis(DTF)pyrene), in oil, i.e., a w|o interface. At a large ITIES the reaction is spontaneous, rapid, and proceeds via transfer of AuCl4- to the oil phase, followed by homogeneous electron transfer generating uncontrolled polymer growth with larger (∼50 nm) Au nanoparticles (NPs). Thus, miniaturization facilitates external, potential control and limits the reaction pathway. Atomic (AFM) and Kelvin probe force microscopies (KPFM) imaged the topography and work function distribution of the as-prepared films. The latter was linked to nanocluster distribution.
Collapse
Affiliation(s)
- Reza Moshrefi
- Memorial University of Newfoundland, Core Science Facility, 45 Arctic Ave, St. John's, NL, Canada, A1C 5S7.
| | - Katelyn Ryan
- Memorial University of Newfoundland, Core Science Facility, 45 Arctic Ave, St. John's, NL, Canada, A1C 5S7.
| | - Evan P Connors
- Memorial University of Newfoundland, Core Science Facility, 45 Arctic Ave, St. John's, NL, Canada, A1C 5S7.
| | - Joshua C Walsh
- Memorial University of Newfoundland, Core Science Facility, 45 Arctic Ave, St. John's, NL, Canada, A1C 5S7.
| | - Erika Merschrod
- Memorial University of Newfoundland, Core Science Facility, 45 Arctic Ave, St. John's, NL, Canada, A1C 5S7.
| | - Graham J Bodwell
- Memorial University of Newfoundland, Core Science Facility, 45 Arctic Ave, St. John's, NL, Canada, A1C 5S7.
| | - Talia Jane Stockmann
- Memorial University of Newfoundland, Core Science Facility, 45 Arctic Ave, St. John's, NL, Canada, A1C 5S7.
| |
Collapse
|
11
|
Work Function of Layered Graphene Prepared by Chemical Vapor Deposition in High Vacuum. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2022. [DOI: 10.1380/ejssnt.2023-011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
12
|
Dou W, Yin Z, Zhang Y, Deng H, Dai N. Two-Dimensional Perovskite (PEA) 2PbI 4 Two-Color Blue-Green Photodetector. NANOMATERIALS 2022; 12:nano12152556. [PMID: 35893524 PMCID: PMC9331230 DOI: 10.3390/nano12152556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/17/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022]
Abstract
Perovskite materials have been widely used to fabricate solar cells, laser diodes and other photodevices, owing to the advantage of high absorption coefficient, long carrier life and shallow defect energy levels. However, due to easy hydrolysis, it is difficult to fabricate perovskite micro-nano devices. Herein, we developed a water-free device fabrication technology and fabricated a two-dimensional (C6H5C2H4NH3)2PbI4 ((PEA)2PbI4) two-color blue-green light detector, which exhibits high detection performance under the illumination of two-color lasers (λ = 460 nm, 532 nm). Compared with bulk devices, the dark current of the fabricated devices (10−11 A) was reduced by 2 orders of magnitude. The peak responsivity and detectivity are about 1 A/W and 1011 Jones, respectively. The photodetection performance of the device is basically the same under the two-color lasers. Our results provide a new process to fabricate perovskite microelectronic devices, and the fabricated photodetector shows great application prospects in underwater detection, owing to the blue-green window existing in water.
Collapse
Affiliation(s)
- Wei Dou
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China; (W.D.); (Z.Y.); (Y.Z.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Physical Science and Technology, Shanghai Tech University, Shanghai 201210, China
| | - Ziwei Yin
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China; (W.D.); (Z.Y.); (Y.Z.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi Zhang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China; (W.D.); (Z.Y.); (Y.Z.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huiyong Deng
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China; (W.D.); (Z.Y.); (Y.Z.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- Zhejiang Laboratory, Hangzhou 311100, China
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- Correspondence: (H.D.); (N.D.)
| | - Ning Dai
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China; (W.D.); (Z.Y.); (Y.Z.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- Zhejiang Laboratory, Hangzhou 311100, China
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou 213164, China
- Correspondence: (H.D.); (N.D.)
| |
Collapse
|
13
|
Brouillard M, Bercu N, Zschieschang U, Simonetti O, Mittapalli R, Klauk H, Giraudet L. Experimental determination of the lateral resolution of surface electric potential measurements by Kelvin probe force microscopy using biased electrodes separated by a nanoscale gap and application to thin-film transistors. NANOSCALE ADVANCES 2022; 4:2018-2028. [PMID: 36133418 PMCID: PMC9417587 DOI: 10.1039/d1na00824b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 03/15/2022] [Indexed: 06/16/2023]
Abstract
A method is proposed to estimate the lateral resolution of surface potential profile measurements using Kelvin probe force microscopy (KPFM) on operating electronic devices. De-embedding the measured profile from the system response is required for various applications, such as contact characterization of thin-film transistors, or local longitudinal electric field measurements. A method is developed based on the measurement of the electric potential profile of two metallic electrodes separated by a nano-gap, providing a quasi-planar configuration. The electrodes are independently biased so as to produce an abrupt and well-controlled potential step. This calibration sample is used to measure the system impulse response in various configurations. Due to the application constrains, the KPFM method employed here is based on a dual-pass mode, demonstrated to provide reliable measurements on operating electronic devices. The method is applied to two types of conductive AFM probes. Measurements are performed at different tip-to-sample heights allowing the determination of the lateral resolution of the double-pass method. Detailed description of the measurements and resolution results are given for the present KPFM configuration. The system resolution measurement technique can be extended to other KPFM modes and can be used to monitor the degradation of the tip quality during long measurement campaigns. Finally, the method is applied to the characterization of thin-film transistors, and the effects of contact edge sharpness on the device behavior is discussed. The longitudinal electric field responsible for charge injection at the source-contact edge is successfully estimated and compared for organic thin-film transistors fabricated by stencil lithography or electron-beam lithography.
Collapse
Affiliation(s)
- Mélanie Brouillard
- Laboratoire de Recherche en Nanosciences (LRN EA 4682), Université de Reims Champagne-Ardenne 51100 Reims France
- Max Planck Institute for Solid State Research Stuttgart Germany
| | - Nicolas Bercu
- Laboratoire de Recherche en Nanosciences (LRN EA 4682), Université de Reims Champagne-Ardenne 51100 Reims France
| | | | - Olivier Simonetti
- Laboratoire de Recherche en Nanosciences (LRN EA 4682), Université de Reims Champagne-Ardenne 51100 Reims France
| | - Rakesh Mittapalli
- Laboratoire de Recherche en Nanosciences (LRN EA 4682), Université de Reims Champagne-Ardenne 51100 Reims France
| | - Hagen Klauk
- Max Planck Institute for Solid State Research Stuttgart Germany
| | - Louis Giraudet
- Laboratoire de Recherche en Nanosciences (LRN EA 4682), Université de Reims Champagne-Ardenne 51100 Reims France
| |
Collapse
|
14
|
Impedance Spectroscopy of Encapsulated Single Graphene Layers. NANOMATERIALS 2022; 12:nano12050804. [PMID: 35269292 PMCID: PMC8912308 DOI: 10.3390/nano12050804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 02/21/2022] [Accepted: 02/25/2022] [Indexed: 02/01/2023]
Abstract
In this work, we demonstrate the use of electrical impedance spectroscopy (EIS) for the disentanglement of several dielectric contributions in encapsulated single graphene layers. The dielectric data strongly vary qualitatively with the nominal graphene resistance. In the case of sufficiently low resistance of the graphene layers, the dielectric spectra are dominated by inductive contributions, which allow for disentanglement of the electrode/graphene interface resistance from the intrinsic graphene resistance by the application of an adequate equivalent circuit model. Higher resistance of the graphene layers leads to predominantly capacitive dielectric contributions, and the deconvolution is not feasible due to the experimental high frequency limit of the EIS technique.
Collapse
|
15
|
Setiawan RC, Wu M, Li DY. Dependence of Interfacial Adhesion between Substances on Their Electron Work Functions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:1672-1679. [PMID: 35076231 DOI: 10.1021/acs.langmuir.1c02442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this article, we demonstrate the dependence of the adhesive force (FAd) between two different substances on their electron work functions (EWF or φ) without atomic diffusion involved. The adhesive forces between Si3N4 and a number of metals were measured using an atomic force microscope. It is shown that the larger the difference in φ between the two substances in contact, the larger the FAd. FAd is also influenced by the electron freedom and density (related to the charge availability). An analytical model is proposed to elucidate the underlying mechanism and quantify the adhesive interaction.
Collapse
Affiliation(s)
| | - Mingyu Wu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton AB T6G 2H5, Canada
| | - D Y Li
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton AB T6G 2H5, Canada
| |
Collapse
|
16
|
Samaddar S, Strasdas J, Janßen K, Just S, Johnsen T, Wang Z, Uzlu B, Li S, Neumaier D, Liebmann M, Morgenstern M. Evidence for Local Spots of Viscous Electron Flow in Graphene at Moderate Mobility. NANO LETTERS 2021; 21:9365-9373. [PMID: 34734723 DOI: 10.1021/acs.nanolett.1c01145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Dominating electron-electron scattering enables viscous electron flow exhibiting hydrodynamic current density patterns, such as Poiseuille profiles or vortices. The viscous regime has recently been observed in graphene by nonlocal transport experiments and mapping of the Poiseuille profile. Herein, we probe the current-induced surface potential maps of graphene field-effect transistors with moderate mobility using scanning probe microscopy at room temperature. We discover micrometer-sized large areas appearing close to charge neutrality that show current-induced electric fields opposing the externally applied field. By estimating the local scattering lengths from the gate dependence of local in-plane electric fields, we find that electron-electron scattering dominates in these areas as expected for viscous flow. Moreover, we suppress the inverted fields by artificially decreasing the electron-disorder scattering length via mild ion bombardment. These results imply that viscous electron flow is omnipresent in graphene devices, even at moderate mobility.
Collapse
Affiliation(s)
- Sayanti Samaddar
- 2nd Institute of Physics B and JARA-FIT, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| | - Jeff Strasdas
- 2nd Institute of Physics B and JARA-FIT, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
| | - Kevin Janßen
- 2nd Institute of Physics B and JARA-FIT, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
- Peter Grünberg Institute 6 & 9, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Sven Just
- 2nd Institute of Physics B and JARA-FIT, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
- Leibniz Institute for Solid State and Materials Research Dresden (IFW), 01171 Dresden, Germany
| | - Tjorven Johnsen
- 2nd Institute of Physics B and JARA-FIT, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
| | - Zhenxing Wang
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany
| | - Burkay Uzlu
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany
- Chair of Electronic Devices, RWTH Aachen University, 52074 Aachen, Germany
| | - Sha Li
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany
| | - Daniel Neumaier
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany
- University of Wuppertal, 42285 Wuppertal, Germany
| | - Marcus Liebmann
- 2nd Institute of Physics B and JARA-FIT, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
| | - Markus Morgenstern
- 2nd Institute of Physics B and JARA-FIT, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany
| |
Collapse
|
17
|
Nurmakanov Y, Kalimuldina G, Nauryzbayev G, Adair D, Bakenov Z. Structural and Chemical Modifications Towards High-Performance of Triboelectric Nanogenerators. NANOSCALE RESEARCH LETTERS 2021; 16:122. [PMID: 34328566 PMCID: PMC8324689 DOI: 10.1186/s11671-021-03578-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 07/21/2021] [Indexed: 06/01/2023]
Abstract
Harvesting abundant mechanical energy has been considered one of the promising technologies for developing autonomous self-powered active sensors, power units, and Internet-of-Things devices. Among various energy harvesting technologies, the triboelectric harvesters based on contact electrification have recently attracted much attention because of their advantages such as high performance, light weight, and simple design. Since the first triboelectric energy-harvesting device was reported, the continuous investigations for improving the output power have been carried out. This review article covers various methods proposed for the performance enhancement of triboelectric nanogenerators (TENGs), such as a triboelectric material selection, surface modification through the introduction of micro-/nano-patterns, and surface chemical functionalization, injecting charges, and their trapping. The main purpose of this work is to highlight and summarize recent advancements towards enhancing the TENG technology performance through implementing different approaches along with their potential applications. This paper presents a comprehensive review of the TENG technology and its factors affecting the output power as material selection, surface physical and chemical modification, charge injection, and trapping techniques.
Collapse
Affiliation(s)
- Yerzhan Nurmakanov
- School of Engineering and Digital Sciences, Nazarbayev University, Kabanbay Batyr Ave. 53, Nur-Sultan, 010000, Kazakhstan
| | - Gulnur Kalimuldina
- Department of Mechanical and Aerospace Engineering, School of Engineering and Digital Sciences, Nazarbayev University, Kabanbay Batyr Ave. 53, Nur-Sultan, 010000, Kazakhstan.
| | - Galymzhan Nauryzbayev
- Department of Electrical and Computer Engineering, School of Engineering and Digital Sciences, Nazarbayev University, Kabanbay Batyr Ave. 53, Nur-Sultan, 010000, Kazakhstan
| | - Desmond Adair
- Department of Mechanical and Aerospace Engineering, School of Engineering and Digital Sciences, Nazarbayev University, Kabanbay Batyr Ave. 53, Nur-Sultan, 010000, Kazakhstan
| | - Zhumabay Bakenov
- Department of Chemical and Materials Engineering, School of Engineering and Digital Sciences, Nazarbayev University, Kabanbay Batyr Ave. 53, Nur-Sultan, 010000, Kazakhstan.
| |
Collapse
|
18
|
Zheng J, Miao T, Xu R, Ping X, Wu Y, Lu Z, Zhang Z, Hu D, Liu L, Zhang Q, Li D, Cheng Z, Ma W, Xie L, Jiao L. Chemical Synthesis and Integration of Highly Conductive PdTe 2 with Low-Dimensional Semiconductors for p-Type Transistors with Low Contact Barriers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2101150. [PMID: 34057254 DOI: 10.1002/adma.202101150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Low-dimensional semiconductors provide promising ultrathin channels for constructing more-than-Moore devices. However, the prominent contact barriers at the semiconductor-metal electrodes interfaces greatly limit the performance of the obtained devices. Here, a chemical approach is developed for the construction of p-type field-effect transistors (FETs) with low contact barriers by achieving the simultaneous synthesis and integration of 2D PdTe2 with various low-dimensional semiconductors. The 2D PdTe2 synthesized through a quasi-liquid process exhibits high electrical conductivity (≈4.3 × 106 S m-1 ) and thermal conductivity (≈130 W m-1 K-1 ), superior to other transition metal dichalcogenides (TMDCs) and even higher than some metals. In addition, PdTe2 electrodes with desired geometry can be synthesized directly on 2D MoTe2 and other semiconductors to form high-performance p-type FETs without any further treatment. The chemically derived atomically ordered PdTe2 -MoTe2 interface results in significantly reduced contact barrier (65 vs 240 meV) and thus increases the performance of the obtained devices. This work demonstrates the great potential of 2D PdTe2 as contact materials and also opens up a new avenue for the future device fabrication through the chemical construction and integration of 2D components.
Collapse
Affiliation(s)
- Jingying Zheng
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
- College of Materials Science and Engineering, Fuzhou University, Fujian, 350108, China
| | - Tingting Miao
- Beijing Key Laboratory of Process Fluid Filtration and Separation, College of Mechanical and Transportation Engineering, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Rui Xu
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Renmin University of China, Beijing, 100872, China
| | - Xiaofan Ping
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yueyang Wu
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Zhixing Lu
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Ziming Zhang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
- Institute of Optical Crystalline Materials, College of Chemistry, Fuzhou University, Fuzhou, 350108, China
| | - Dake Hu
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Lina Liu
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Qi Zhang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Dawei Li
- Beijing Key Laboratory of Process Fluid Filtration and Separation, College of Mechanical and Transportation Engineering, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Zhihai Cheng
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Renmin University of China, Beijing, 100872, China
| | - Weigang Ma
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Liming Xie
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Liying Jiao
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| |
Collapse
|
19
|
Behn WA, Krebs ZJ, Smith KJ, Watanabe K, Taniguchi T, Brar VW. Measuring and Tuning the Potential Landscape of Electrostatically Defined Quantum Dots in Graphene. NANO LETTERS 2021; 21:5013-5020. [PMID: 34096737 DOI: 10.1021/acs.nanolett.1c00791] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We use Kelvin probe force microscopy (KPFM) to probe the carrier-dependent potential of an electrostatically defined quantum dot (QD) in a graphene/hexagonal boron nitride (hBN) heterostructure. We show that gate-dependent measurements enable a calibration scheme that corrects for uncertainty inherent in typical KPFM measurements and accurately reconstructs the potential well profile. Our measurements reveal how the well changes with carrier concentration, which we associate with the nonlinear dependence of graphene's work function on carrier density. These changes shift the energy levels of quasi-bound states in the QD which we can measure via scanning tunneling spectroscopy (STS). We show that the experimentally extracted energy levels closely compare with wave functions calculated from the reconstructed KPFM data. This methodology, where KPFM and STS data are simultaneously acquired from 2D materials, allows the quasiparticle response to an electrostatic potential to be determined in a self-consistent way.
Collapse
Affiliation(s)
- Wyatt A Behn
- Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706, United States
| | - Zachary J Krebs
- Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706, United States
| | - Keenan J Smith
- Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706, United States
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Victor W Brar
- Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706, United States
| |
Collapse
|
20
|
Graphene on SiC Substrate as Biosensor: Theoretical Background, Preparation, and Characterization. MATERIALS 2021; 14:ma14030590. [PMID: 33513840 PMCID: PMC7865904 DOI: 10.3390/ma14030590] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/17/2021] [Accepted: 01/20/2021] [Indexed: 02/01/2023]
Abstract
This work is devoted to the development and optimization of the parameters of graphene-based sensors. The graphene films used in the present study were grown on semi-insulating 6H-SiC substrates by thermal decomposition of SiC at the temperature of ~1700 °C. The results of measurements by Auger and Raman spectroscopies confirmed the presence of single-layer graphene on the silicon carbide surface. Model approach to the theory of adsorption on epitaxial graphene is presented. It is demonstrated that the Green-function method in conjunction with the simple substrate models permit one to obtain analytical results for the charge transfer between adsorbed molecules and substrate. The sensor structure was formed on the graphene film by laser. Initially, a simpler gas sensor was made. The sensors developed in this study demonstrated sensitivity to the NO2 concentration at the level of 1–0.01 ppb. The results obtained in the course of development and the results of testing of the graphene-based sensor for detection of protein molecules are also presented. The biosensor was fabricated by the technology previously developed for the gas sensor. The working capacity of the biosensor was tested with an immunochemical system constituted by fluorescein and monoclonal antibodies (mAbs) binding this dye.
Collapse
|
21
|
Leng K, Wang L, Shao Y, Abdelwahab I, Grinblat G, Verzhbitskiy I, Li R, Cai Y, Chi X, Fu W, Song P, Rusydi A, Eda G, Maier SA, Loh KP. Electron tunneling at the molecularly thin 2D perovskite and graphene van der Waals interface. Nat Commun 2020; 11:5483. [PMID: 33127900 PMCID: PMC7599242 DOI: 10.1038/s41467-020-19331-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 10/07/2020] [Indexed: 11/17/2022] Open
Abstract
Quasi-two-dimensional perovskites have emerged as a new material platform for optoelectronics on account of its intrinsic stability. A major bottleneck to device performance is the high charge injection barrier caused by organic molecular layers on its basal plane, thus the best performing device currently relies on edge contact. Herein, by leveraging on van der Waals coupling and energy level matching between two-dimensional Ruddlesden-Popper perovskite and graphene, we show that the plane-contacted perovskite and graphene interface presents a lower barrier than gold for charge injection. Electron tunneling across the interface occurs via a gate-tunable, direct tunneling-to-field emission mechanism with increasing bias, and photoinduced charge transfer occurs at femtosecond timescale (~50 fs). Field effect transistors fabricated on molecularly thin Ruddlesden-Popper perovskite using graphene contact exhibit electron mobilities ranging from 0.1 to 0.018 cm2V−1s−1 between 1.7 to 200 K. Scanning tunneling spectroscopy studies reveal layer-dependent tunneling barrier and domain size on few-layered Ruddlesden-Popper perovskite. Insulating molecular layers on the basal plane of 2D perovskite is a major bottleneck for charge injection that limiting device performance. Here, the authors show that plane-contacted graphene functions as a low barrier and gate-tunable contact to overcome this limitation.
Collapse
Affiliation(s)
- Kai Leng
- Department of Chemistry, National University of Singapore, Singapore, Singapore.,Center for Advanced 2D Materials and Graphene Research Centre, Singapore, Singapore
| | - Lin Wang
- Department of Chemistry, National University of Singapore, Singapore, Singapore.,Center for Advanced 2D Materials and Graphene Research Centre, Singapore, Singapore
| | - Yan Shao
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Ibrahim Abdelwahab
- Department of Chemistry, National University of Singapore, Singapore, Singapore.,Center for Advanced 2D Materials and Graphene Research Centre, Singapore, Singapore.,Department of Physics, Imperial College London, London, SW7 2AZ, UK
| | - Gustavo Grinblat
- Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, 80539, München, Germany
| | - Ivan Verzhbitskiy
- Center for Advanced 2D Materials and Graphene Research Centre, Singapore, Singapore.,Department of Physics, National University of Singapore, Singapore, Singapore
| | - Runlai Li
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Yongqing Cai
- Institute of Applied Physics and Materials Engineering, University of Macau, Macau, China
| | - Xiao Chi
- Department of Chemistry, National University of Singapore, Singapore, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, 117603, Singapore, Singapore
| | - Wei Fu
- Department of Chemistry, National University of Singapore, Singapore, Singapore.,Center for Advanced 2D Materials and Graphene Research Centre, Singapore, Singapore
| | - Peng Song
- Department of Chemistry, National University of Singapore, Singapore, Singapore.,Center for Advanced 2D Materials and Graphene Research Centre, Singapore, Singapore
| | - Andrivo Rusydi
- Department of Physics, National University of Singapore, Singapore, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, 117603, Singapore, Singapore
| | - Goki Eda
- Department of Chemistry, National University of Singapore, Singapore, Singapore.,Center for Advanced 2D Materials and Graphene Research Centre, Singapore, Singapore.,Department of Physics, National University of Singapore, Singapore, Singapore
| | - Stefan A Maier
- Department of Physics, Imperial College London, London, SW7 2AZ, UK.,Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, 80539, München, Germany
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, Singapore, Singapore. .,Center for Advanced 2D Materials and Graphene Research Centre, Singapore, Singapore.
| |
Collapse
|
22
|
Heterogeneous optoelectronic characteristics of Si micropillar arrays fabricated by metal-assisted chemical etching. Sci Rep 2020; 10:16349. [PMID: 33004988 PMCID: PMC7530667 DOI: 10.1038/s41598-020-73445-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/07/2020] [Indexed: 11/24/2022] Open
Abstract
Recent progress achieved in metal-assisted chemical etching (MACE) has enabled the production of high-quality micropillar arrays for various optoelectronic applications. Si micropillars produced by MACE often show a porous Si/SiOx shell on crystalline pillar cores introduced by local electrochemical reactions. In this paper, we report the distinct optoelectronic characteristics of the porous Si/SiOx shell correlated to their chemical compositions. Local photoluminescent (PL) images obtained with an immersion oil objective lens in confocal microscopy show a red emission peak (≈ 650 nm) along the perimeter of the pillars that is threefold stronger compared to their center. On the basis of our analysis, we find an unexpected PL increase (≈ 540 nm) at the oil/shell interface. We suggest that both PL enhancements are mainly attributed to the porous structures, a similar behavior observed in previous MACE studies. Surface potential maps simultaneously recorded with topography reveal a significantly high surface potential on the sidewalls of MACE-synthesized pillars (+ 0.5 V), which is restored to the level of planar Si control (− 0.5 V) after removing SiOx in hydrofluoric acid. These distinct optoelectronic characteristics of the Si/SiOx shell can be beneficial for various sensor architectures.
Collapse
|
23
|
Sainz R, Del Pozo M, Vilas-Varela M, Castro-Esteban J, Pérez Corral M, Vázquez L, Blanco E, Peña D, Martín-Gago JA, Ellis GJ, Petit-Domínguez MD, Quintana C, Casero E. Chemically synthesized chevron-like graphene nanoribbons for electrochemical sensors development: determination of epinephrine. Sci Rep 2020; 10:14614. [PMID: 32884078 PMCID: PMC7471882 DOI: 10.1038/s41598-020-71554-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 08/18/2020] [Indexed: 11/09/2022] Open
Abstract
We employ chevron-like graphene nanoribbons (GNRs) synthesized by a solution-based chemical route to develop a novel electrochemical sensor for determination of the neurotransmitter epinephrine (EPI). The sensor surface, a glassy carbon electrode modified with GNRs, is characterized by atomic force microscopy, scanning electron microscopy and Raman spectroscopy, which show that the electrode surface modification comprises of bi-dimensional multilayer-stacked GNRs that retain their molecular structure. The charge transfer process occurring at the electrode interface is evaluated by electrochemical impedance spectroscopy. The sensor is applied to the determination of EPI, employing as an analytical signal the reduction peak corresponding to the epinephrinechrome–leucoepinephrinechrome transition (E = − 0.25 V) instead of the oxidation peak usually employed in the literature (E = + 0.6 V) in order to minimize interferences. The results obtained demonstrate that chevron-like nanoribbons synthesized by solution methods exhibit reliable electrocatalytic activity for EPI determination. Using differential pulse voltammetry, we obtain a linear concentration range from 6.4 × 10–6 to 1.0 × 10–4 M and a detection limit of 2.1 × 10–6 M. The applicability of the sensor was evaluated by determining EPI in pharmaceutical samples with satisfactory results.
Collapse
Affiliation(s)
- Raquel Sainz
- Departamento de Química Analítica y Análisis Instrumental, Facultad de Ciencias, Campus de Excelencia de la Universidad Autónoma de Madrid, c/ Francisco Tomás y Valiente, Nº7, 28049, Madrid, Spain
| | - María Del Pozo
- Departamento de Química Analítica y Análisis Instrumental, Facultad de Ciencias, Campus de Excelencia de la Universidad Autónoma de Madrid, c/ Francisco Tomás y Valiente, Nº7, 28049, Madrid, Spain
| | - Manuel Vilas-Varela
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | - Jesús Castro-Esteban
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | - María Pérez Corral
- Departamento de Química Analítica y Análisis Instrumental, Facultad de Ciencias, Campus de Excelencia de la Universidad Autónoma de Madrid, c/ Francisco Tomás y Valiente, Nº7, 28049, Madrid, Spain
| | - Luis Vázquez
- ESISNA group, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), c/ Sor Juana Inés de la Cruz Nº3, 28049, Madrid, Spain
| | - Elías Blanco
- Departamento de Química Analítica y Análisis Instrumental, Facultad de Ciencias, Campus de Excelencia de la Universidad Autónoma de Madrid, c/ Francisco Tomás y Valiente, Nº7, 28049, Madrid, Spain
| | - Diego Peña
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | - José A Martín-Gago
- ESISNA group, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), c/ Sor Juana Inés de la Cruz Nº3, 28049, Madrid, Spain
| | - Gary J Ellis
- Departamento de Física de Polímeros, Elastómeros y Aplicaciones Energéticas, Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), c/ Juan de la Cierva, 3, 28006, Madrid, Spain
| | - María Dolores Petit-Domínguez
- Departamento de Química Analítica y Análisis Instrumental, Facultad de Ciencias, Campus de Excelencia de la Universidad Autónoma de Madrid, c/ Francisco Tomás y Valiente, Nº7, 28049, Madrid, Spain
| | - Carmen Quintana
- Departamento de Química Analítica y Análisis Instrumental, Facultad de Ciencias, Campus de Excelencia de la Universidad Autónoma de Madrid, c/ Francisco Tomás y Valiente, Nº7, 28049, Madrid, Spain
| | - Elena Casero
- Departamento de Química Analítica y Análisis Instrumental, Facultad de Ciencias, Campus de Excelencia de la Universidad Autónoma de Madrid, c/ Francisco Tomás y Valiente, Nº7, 28049, Madrid, Spain.
| |
Collapse
|
24
|
Fukuda M, Islam MS, Mashimo T, Hayami S. Pulsed Plasma Assisted Cl-Doped Graphene Nano Dots with Semiconducting Property. CHEM LETT 2020. [DOI: 10.1246/cl.200108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Masahiro Fukuda
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
| | - Md. Saidul Islam
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
| | - Tsutomu Mashimo
- Institute of Pulsed Power Science (IPPS), Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
| | - Shinya Hayami
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
- Institute of Pulsed Power Science (IPPS), Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
| |
Collapse
|
25
|
Milošević IR, Vasić B, Matković A, Vujin J, Aškrabić S, Kratzer M, Griesser T, Teichert C, Gajić R. Single-step fabrication and work function engineering of Langmuir-Blodgett assembled few-layer graphene films with Li and Au salts. Sci Rep 2020; 10:8476. [PMID: 32439854 PMCID: PMC7242397 DOI: 10.1038/s41598-020-65379-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 04/28/2020] [Indexed: 11/08/2022] Open
Abstract
To implement large-area solution-processed graphene films in low-cost transparent conductor applications, it is necessary to have the control over the work function (WF) of the film. In this study we demonstrate a straightforward single-step chemical approach for modulating the work function of graphene films. In our approach, chemical doping of the film is introduced at the moment of its formation. The films are self-assembled from liquid-phase exfoliated few-layer graphene sheet dispersions by Langmuir-Blodgett technique at the water-air interfaces. To achieve a single-step chemical doping, metal standard solutions are introduced instead of water. Li standard solutions (LiCl, LiNO3, Li2CO3) were used as n-dopant, and gold standard solution, H(AuCl4), as p-dopant. Li based salts decrease the work function, while Au based salts increase the work function of the entire film. The maximal doping in both directions yields a significant range of around 0.7 eV for the work function modulation. In all cases when Li-based salts are introduced, electrical properties of the film deteriorate. Further, lithium nitrate (LiNO3) was selected as the best choice for n-type doping since it provides the largest work function modulation (by 400 meV), and the least influence on the electrical properties of the film.
Collapse
Affiliation(s)
- Ivana R Milošević
- Laboratory for Graphene, other 2D Materials and Ordered Nanostructures of Center for Solid State Physics and New Materials, Institute of Physics, University of Belgrade, Pregrevica 118, 11080, Belgrade, Serbia.
| | - Borislav Vasić
- Laboratory for Graphene, other 2D Materials and Ordered Nanostructures of Center for Solid State Physics and New Materials, Institute of Physics, University of Belgrade, Pregrevica 118, 11080, Belgrade, Serbia
| | - Aleksandar Matković
- Institute of Physics, Montanuniversität Leoben, Franz Josef Str. 18, 8700, Leoben, Austria.
| | - Jasna Vujin
- Laboratory for Graphene, other 2D Materials and Ordered Nanostructures of Center for Solid State Physics and New Materials, Institute of Physics, University of Belgrade, Pregrevica 118, 11080, Belgrade, Serbia
| | - Sonja Aškrabić
- Nanostructured Matter Laboratory of Center for Solid State Physics and New Materials, Institute of Physics, University of Belgrade, Pregrevica 118, 11080, Belgrade, Serbia
| | - Markus Kratzer
- Institute of Physics, Montanuniversität Leoben, Franz Josef Str. 18, 8700, Leoben, Austria
| | - Thomas Griesser
- Institute of Chemistry of Polymeric Materials, Montanuniversität Leoben, Otto-Gloeckel-Straße 2, 8700, Leoben, Austria
| | - Christian Teichert
- Institute of Physics, Montanuniversität Leoben, Franz Josef Str. 18, 8700, Leoben, Austria
| | - Radoš Gajić
- Laboratory for Graphene, other 2D Materials and Ordered Nanostructures of Center for Solid State Physics and New Materials, Institute of Physics, University of Belgrade, Pregrevica 118, 11080, Belgrade, Serbia
| |
Collapse
|
26
|
De Cecco A, Prudkovskiy VS, Wander D, Ganguly R, Berger C, de Heer WA, Courtois H, Winkelmann CB. Non-Invasive Nanoscale Potentiometry and Ballistic Transport in Epigraphene Nanoribbons. NANO LETTERS 2020; 20:3786-3790. [PMID: 32271586 DOI: 10.1021/acs.nanolett.0c00838] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The recent observation of non-classical electron transport regimes in two-dimensional materials has called for new high-resolution non-invasive techniques to locally probe electronic properties. We introduce a novel hybrid scanning probe technique to map the local resistance and electrochemical potential with nm- and μV resolution, and we apply it to study epigraphene nanoribbons grown on the sidewalls of SiC substrate steps. Remarkably, the potential drop is non-uniform along the ribbons, and μm-long segments show no potential variation with distance. The potential maps are in excellent agreement with measurements of the local resistance. This reveals ballistic transport, compatible with μm-long room-temperature electronic mean-free paths.
Collapse
Affiliation(s)
- Alessandro De Cecco
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble 38042, France
| | - Vladimir S Prudkovskiy
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble 38042, France
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - David Wander
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble 38042, France
| | - Rini Ganguly
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble 38042, France
| | - Claire Berger
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble 38042, France
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Walt A de Heer
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Tianjin International Center for Nanoparticles and Nanosystems (TICNN), Tianjin University, Tianjin 300072, China
| | - Hervé Courtois
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble 38042, France
| | - Clemens B Winkelmann
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble 38042, France
| |
Collapse
|
27
|
Dappe YJ, Almadori Y, Dau MT, Vergnaud C, Jamet M, Paillet C, Journot T, Hyot B, Pochet P, Grévin B. Charge transfers and charged defects in WSe 2/graphene-SiC interfaces. NANOTECHNOLOGY 2020; 31:255709. [PMID: 32182596 DOI: 10.1088/1361-6528/ab8083] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report on Kelvin probe force microscopy (KPFM) and density functional theory (DFT) investigations of charge transfers in vertical heterojunctions between tungsten diselenide (WSe2) layers and graphene on silicon carbide substrates. The experimental data reveal the existence of an interface dipole, which is shown by DFT to originate from the neutralization of the graphene n-doping by an electron transfer towards the transition metal dichalcogenide (TMD) layer. The relative vacuum level shift probed by KPFM between the TMD and the substrate stays constant when passing from monolayer to bilayer graphene, which confirms that the Schottky-Mott model can be rigorously applied to these interfaces by taking into account the charge transfer from the substrate to the TMD. DFT calculations show that the first TMD layer absorbs almost all the excess charges contained in the graphene, and that the second TMD layer shall not play a significant role in the electrostatics of the system. Negatively charged defect at the TMD edges contribute however to the electrostatic landscape probed by KPFM on both TMD layers.
Collapse
Affiliation(s)
- Y J Dappe
- SPEC, CEA, CNRS, Université Paris Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Wu J, Chen J, Wang C, Zhou Y, Ba K, Xu H, Bao W, Xu X, Carlsson A, Lazar S, Meingast A, Sun Z, Deng H. Metal-Organic Framework for Transparent Electronics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1903003. [PMID: 32328418 PMCID: PMC7175255 DOI: 10.1002/advs.201903003] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/26/2019] [Indexed: 05/21/2023]
Abstract
Electronics allowing for visible light to pass through are attractive, where a key challenge is to make the core functional units transparent. Here, it is shown that transparent electronics can be constructed by epitaxial growth of metal-organic frameworks (MOFs) on single-layer graphene (SLG) to give a desirable transparency of 95.7% to 550 nm visible light and an electrical conductivity of 4.0 × 104 S m-1. Through lattice and symmetry match, collective alignment of MOF pores and dense packing of MOFs vertically on SLG are achieved, as directly visualized by electron microscopy. These MOF-on-SLG constructs are capable of room-temperature recognition of gas molecules at the ppb level with a linear range from 10 to 108 ppb, providing real-time gas monitoring function in transparent electronics. The corresponding devices can be fabricated on flexible substrates with large size, 3 × 5 cm, and afford continuous folding for more than 200 times without losing conductivity or transparency.
Collapse
Affiliation(s)
- Jie Wu
- Key Laboratory of Biomedical Polymers‐Ministry of EducationCollege of Chemistry and Molecular ScienceWuhan UniversityWuhan430072P. R. China
| | - Jinhang Chen
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative MaterialsFudan UniversityShanghai200433P. R. China
| | - Chao Wang
- Key Laboratory of Biomedical Polymers‐Ministry of EducationCollege of Chemistry and Molecular ScienceWuhan UniversityWuhan430072P. R. China
| | - Yi Zhou
- Key Laboratory of Biomedical Polymers‐Ministry of EducationCollege of Chemistry and Molecular ScienceWuhan UniversityWuhan430072P. R. China
| | - Kun Ba
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative MaterialsFudan UniversityShanghai200433P. R. China
| | - Hu Xu
- School of MicroelectronicFudan UniversityShanghai200433P. R. China
| | - Wenzhong Bao
- School of MicroelectronicFudan UniversityShanghai200433P. R. China
| | - Xiaohui Xu
- Key Laboratory of Biomedical Polymers‐Ministry of EducationCollege of Chemistry and Molecular ScienceWuhan UniversityWuhan430072P. R. China
| | - Anna Carlsson
- Thermo Fisher ScientificMaterials & Structural Analysis5651 GGEindhovenThe Netherlands
| | - Sorin Lazar
- Thermo Fisher ScientificMaterials & Structural Analysis5651 GGEindhovenThe Netherlands
| | - Arno Meingast
- Thermo Fisher ScientificMaterials & Structural Analysis5651 GGEindhovenThe Netherlands
| | - Zhengzong Sun
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative MaterialsFudan UniversityShanghai200433P. R. China
| | - Hexiang Deng
- Key Laboratory of Biomedical Polymers‐Ministry of EducationCollege of Chemistry and Molecular ScienceWuhan UniversityWuhan430072P. R. China
| |
Collapse
|
29
|
Lähderanta E, Lebedev AA, Shakhov MA, Stamov VN, Lisunov KG, Lebedev SP. Low-temperature quantum magnetotransport of graphene on SiC (0 0 0 1) in pulsed magnetic fields up to 30 T. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:115704. [PMID: 31770736 DOI: 10.1088/1361-648x/ab5bb6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Resistivity, ρ(T), and magnetoresistance (MR) are investigated in graphene grown on SiC (0 0 0 1), at temperatures between T ~ 4-85 K in pulsed magnetic fields of B up to 30 T. According to the Raman spectroscopy and Kelvin-probe microscopy data, the material is a single-layer graphene containing ~20% double-layer islands with a submicron scale and relatively high amount of intrinsic defects. The dependence of ρ(T) exhibits a minimum at temperature T m ~ 30 K. The low-field Hall data have yielded a high electron concentration, n R ≈ 1.4 × 1013 cm-2 connected to intrinsic defects, and a mobility value of µ H ~ 300 cm2 (Vs)-1 weakly depending on T. Analysis of the Shubnikov-de Haas oscillations of MR, observed between B ~ 10-30 T, permitted to establish existence of the Berry phase β ≈ 0.55 and the cyclotron mass, m c ≈ 0.07 (in units of the free electron mass) close to expected values for the single-layer graphene, respectively. MR at 4.2 K is negative up to B ~ 9 T, exhibiting a minimum near 3 T. Analysis of MR within the whole range of B = 0-10 T below the onset of the SdH effect has revealed three contributions, connected to (i) the classical MR effect, (ii) the weak localization, and (iii) the electron-electron interaction. Analysis of the ρ(T) dependence has confirmed the presence of the contributions (ii) and (iii), revealing a high importance of the electron-electron scattering. As a result, characteristic relaxation times were obtained; an important role of the spin-orbit interaction in the material has been demonstrated, too.
Collapse
Affiliation(s)
- E Lähderanta
- Department of Physics, LUT University, PO Box 20, FIN-53851, Lappeenranta, Finland
| | | | | | | | | | | |
Collapse
|
30
|
Towards standardisation of contact and contactless electrical measurements of CVD graphene at the macro-, micro- and nano-scale. Sci Rep 2020; 10:3223. [PMID: 32081982 PMCID: PMC7035257 DOI: 10.1038/s41598-020-59851-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 12/05/2019] [Indexed: 11/16/2022] Open
Abstract
Graphene has become the focus of extensive research efforts and it can now be produced in wafer-scale. For the development of next generation graphene-based electronic components, electrical characterization of graphene is imperative and requires the measurement of work function, sheet resistance, carrier concentration and mobility in both macro-, micro- and nano-scale. Moreover, commercial applications of graphene require fast and large-area mapping of electrical properties, rather than obtaining a single point value, which should be ideally achieved by a contactless measurement technique. We demonstrate a comprehensive methodology for measurements of the electrical properties of graphene that ranges from nano- to macro- scales, while balancing the acquisition time and maintaining the robust quality control and reproducibility between contact and contactless methods. The electrical characterisation is achieved by using a combination of techniques, including magneto-transport in the van der Pauw geometry, THz time-domain spectroscopy mapping and calibrated Kelvin probe force microscopy. The results exhibit excellent agreement between the different techniques. Moreover, we highlight the need for standardized electrical measurements in highly controlled environmental conditions and the application of appropriate weighting functions.
Collapse
|
31
|
Al-Dainy GA, Watanabe F, Kannarpady GK, Ghosh A, Berry B, Biris AS, Bourdo SE. Optimizing Lignosulfonic Acid-Grafted Polyaniline as a Hole-Transport Layer for Inverted CH 3NH 3PbI 3 Perovskite Solar Cells. ACS OMEGA 2020; 5:1887-1901. [PMID: 32039325 PMCID: PMC7003196 DOI: 10.1021/acsomega.9b03451] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 12/23/2019] [Indexed: 06/01/2023]
Abstract
A conducting polymer of lignosulfonic acid-grafted, polyaniline-doped camphorsulfonic acid (LS-PANI-CSA), created via a low-temperature solution process, has been explored as an efficient hole-transport layer (HTL) for inverted single cation-anion CH3NH3PbI3 perovskite solar cells. The performance of the solar cell was optimized in this study by tuning the morphology and work function of LS-PANI-CSA films using dimethylsulfoxide (DMSO) as a solvent in treatment. Results showed that DMSO washing enhanced the electronic properties of the LS-PANI-CSA film and increased its hydrophobicity, which is very important for perovskite growth. The perovskite active layer deposited onto the DMSO-treated LS-PANI-CSA layer had higher crystallinity with large grain sizes (>5 μm), more uniform and complete surface coverage, and very low pinhole density and PbI2 residues compared to untreated LS-PANI-CSA. These enhancements result in higher device performance and stability. Using DMSO-treated LS-PANI-CSA as an HTL at 15 nm of thickness, a maximum 10.8% power conversion efficiency was obtained in ITO/LS-PANI-CSA/MAPbI3/PCBM/BCP/Ag inverted-device configurations. This was a significant improvement compared to 5.18% for devices based on untreated LS-PANI-CSA and a slight improvement over PEDOT:PSS-based devices with 9.48%. Furthermore, the perovskite based on treated LS-PANI-CSA showed the higher stability compared to both untreated LS-PANI-CSA and PEDOT:PSS HTL-based devices.
Collapse
Affiliation(s)
- Gailan A. Al-Dainy
- Center for Integrative
Nanotechnology Sciences, University of Arkansas
at Little Rock, 2801 S. University Ave., Little Rock, Arkansas 72204, United States
| | - Fumiya Watanabe
- Center for Integrative
Nanotechnology Sciences, University of Arkansas
at Little Rock, 2801 S. University Ave., Little Rock, Arkansas 72204, United States
| | - Ganesh K. Kannarpady
- Center for Integrative
Nanotechnology Sciences, University of Arkansas
at Little Rock, 2801 S. University Ave., Little Rock, Arkansas 72204, United States
| | - Anindya Ghosh
- Department of Chemistry, University of Arkansas at Little Rock, 2801 S. University Ave., Little Rock, Arkansas 72204, United States
| | - Brian Berry
- Department of Chemistry, University of Arkansas at Little Rock, 2801 S. University Ave., Little Rock, Arkansas 72204, United States
| | - Alexandru S. Biris
- Center for Integrative
Nanotechnology Sciences, University of Arkansas
at Little Rock, 2801 S. University Ave., Little Rock, Arkansas 72204, United States
| | - Shawn E. Bourdo
- Center for Integrative
Nanotechnology Sciences, University of Arkansas
at Little Rock, 2801 S. University Ave., Little Rock, Arkansas 72204, United States
| |
Collapse
|
32
|
Alvarez-Fernandez A, Aissou K, Pécastaings G, Hadziioannou G, Fleury G, Ponsinet V. High refractive index in low metal content nanoplasmonic surfaces from self-assembled block copolymer thin films. NANOSCALE ADVANCES 2019; 1:849-857. [PMID: 36132249 PMCID: PMC9473184 DOI: 10.1039/c8na00239h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/21/2018] [Indexed: 05/15/2023]
Abstract
Materials with a high and tunable refractive index are attractive for nanophotonic applications. In this contribution, we propose a straightforward fabrication technique of high-refractive index surfaces based on self-assembled nanostructured block copolymer thin films. The selective and customizable metal incorporation within out-of-plane polymer lamellae produces azimuthally isotropic metallic nanostructures of defined geometries, which were analysed using microscopy and small-angle X-ray scattering techniques. Variable-angle spectroscopic ellipsometry was used to relate the geometrical parameters of the metallic features and the resulting refractive index of the patterned surfaces. In particular, nanostructured gold patterns with a high degree of homogeneity and a gold content as low as 16 vol% reach a refractive index value of more than 3 in the visible domain. Our study thus demonstrates a new route for the preparation of high refractive index surfaces with a low metal content for optical applications.
Collapse
Affiliation(s)
- Alberto Alvarez-Fernandez
- Laboratoire de Chimie des Polymères Organiques (LCPO), CNRS UMR 5629, ENSCPB, Université de Bordeaux 16 Avenue Pey-Berland F-33607 Pessac Cedex France
- Univ. Bordeaux, CNRS, Centre de Recherche Paul Pascal (CRPP) UMR 5031 33600 Pessac France
| | - Karim Aissou
- Laboratoire de Chimie des Polymères Organiques (LCPO), CNRS UMR 5629, ENSCPB, Université de Bordeaux 16 Avenue Pey-Berland F-33607 Pessac Cedex France
| | - Gilles Pécastaings
- Laboratoire de Chimie des Polymères Organiques (LCPO), CNRS UMR 5629, ENSCPB, Université de Bordeaux 16 Avenue Pey-Berland F-33607 Pessac Cedex France
| | - Georges Hadziioannou
- Laboratoire de Chimie des Polymères Organiques (LCPO), CNRS UMR 5629, ENSCPB, Université de Bordeaux 16 Avenue Pey-Berland F-33607 Pessac Cedex France
| | - Guillaume Fleury
- Laboratoire de Chimie des Polymères Organiques (LCPO), CNRS UMR 5629, ENSCPB, Université de Bordeaux 16 Avenue Pey-Berland F-33607 Pessac Cedex France
| | - Virginie Ponsinet
- Univ. Bordeaux, CNRS, Centre de Recherche Paul Pascal (CRPP) UMR 5031 33600 Pessac France
| |
Collapse
|
33
|
Modulating the Work Function of Graphene by Pulsed Plasma Aided Controlled Chlorination. Sci Rep 2018; 8:17392. [PMID: 30478376 PMCID: PMC6255754 DOI: 10.1038/s41598-018-35668-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 11/08/2018] [Indexed: 11/16/2022] Open
Abstract
Chlorine on graphene (G) matrices was doped by pulsed plasma stimulation on graphite electrode submerged in organochlorine solvents (CH2Cl2, CHCl3, CCl4). The study of work function by Kelvin probe force microscopy (KPFM) measurement clearly indicates that Cl-doped G behave like semiconductor and GG@CHCl3 exhibits the lowest value for the work function. We propose that this report not only represents a new route for tuning the semiconductivity of G but also indicates that doping level of halogen on G based carbon framework can be controlled by pulsed plasma treatment of carbon materials on various organohalogen derivatives.
Collapse
|
34
|
Surface potential and thin film quality of low work function metals on epitaxial graphene. Sci Rep 2018; 8:16487. [PMID: 30405192 PMCID: PMC6220296 DOI: 10.1038/s41598-018-34595-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 10/18/2018] [Indexed: 11/09/2022] Open
Abstract
Metal films deposited on graphene are known to influence its electronic properties, but little is known about graphene's interactions with very low work function rare earth metals. Here we report on the work functions of a wide range of metals deposited on n-type epitaxial graphene (EG) as measured by Kelvin Probe Force Microscopy (KPFM). We compare the behaviors of rare earth metals (Pr, Eu, Er, Yb, and Y) with commonly used noble metals (Cr, Cu, Rh, Ni, Au, and Pt). The rare earth films oxidize rapidly, and exhibit unique behaviors when on graphene. We find that the measured work function of the low work function group is consistently higher than predicted, unlike the noble metals, which is likely due to rapid oxidation during measurement. Some of the low work function metals interact with graphene; for example, Eu exhibits bonding anomalies along the metal-graphene perimeter. We observe no correlation between metal work function and photovoltage, implying the metal-graphene interface properties are a more determinant factor. Yb emerges as the best choice for future applications requiring a low-work function electrical contact on graphene. Yb films have the strongest photovoltage response and maintains a relatively low surface roughness, ~5 nm, despite sensitivity to oxidation.
Collapse
|
35
|
Suenaga K, Ji HG, Lin YC, Vincent T, Maruyama M, Aji AS, Shiratsuchi Y, Ding D, Kawahara K, Okada S, Panchal V, Kazakova O, Hibino H, Suenaga K, Ago H. Surface-Mediated Aligned Growth of Monolayer MoS 2 and In-Plane Heterostructures with Graphene on Sapphire. ACS NANO 2018; 12:10032-10044. [PMID: 30232883 DOI: 10.1021/acsnano.8b04612] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Aligned growth of transition metal dichalcogenides and related two-dimensional (2D) materials is essential for the synthesis of high-quality 2D films due to effective stitching of merging grains. Here, we demonstrate the controlled growth of highly aligned molybdenum disulfide (MoS2) on c-plane sapphire with two distinct orientations, which are highly controlled by tuning sulfur concentration. We found that the size of the aligned MoS2 grains is smaller and their photoluminescence is weaker as compared with those of the randomly oriented grains, signifying enhanced MoS2-substrate interaction in the aligned grains. This interaction induces strain in the aligned MoS2, which can be recognized from their high susceptibility to air oxidation. The surface-mediated MoS2 growth on sapphire was further developed to the rational synthesis of an in-plane MoS2-graphene heterostructure connected with the predefined orientation. The in-plane epitaxy was observed by low-energy electron microscopy. Transmission electron microscopy and scanning transmission electron microscopy suggest the alignment of a zigzag edge of MoS2 parallel to a zigzag edge of the neighboring graphene. Moreover, better electrical contact to MoS2 was obtained by the monolayer graphene compared with a conventional metal electrode. Our findings deepen the understanding of the chemical vapor deposition growth of 2D materials and also contribute to the tailored synthesis as well as applications of advanced 2D heterostructures.
Collapse
Affiliation(s)
- Kenshiro Suenaga
- Interdisciplinary Graduate School of Engineering Sciences , Kyushu University , Fukuoka 816-8580 , Japan
| | - Hyun Goo Ji
- Interdisciplinary Graduate School of Engineering Sciences , Kyushu University , Fukuoka 816-8580 , Japan
| | - Yung-Chang Lin
- National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba 305-8565 , Japan
| | - Tom Vincent
- National Physical Laboratory (NPL) , Teddington TW11 0LW , United Kingdom
| | - Mina Maruyama
- Graduate School of Pure and Applied Sciences , University of Tsukuba , Ibaraki 305-8571 , Japan
| | - Adha Sukma Aji
- Interdisciplinary Graduate School of Engineering Sciences , Kyushu University , Fukuoka 816-8580 , Japan
| | - Yoshihiro Shiratsuchi
- Interdisciplinary Graduate School of Engineering Sciences , Kyushu University , Fukuoka 816-8580 , Japan
| | - Dong Ding
- Interdisciplinary Graduate School of Engineering Sciences , Kyushu University , Fukuoka 816-8580 , Japan
| | - Kenji Kawahara
- Global Innovation Center (GIC) , Kyushu University , Fukuoka 816-8580 , Japan
| | - Susumu Okada
- Graduate School of Pure and Applied Sciences , University of Tsukuba , Ibaraki 305-8571 , Japan
| | - Vishal Panchal
- National Physical Laboratory (NPL) , Teddington TW11 0LW , United Kingdom
| | - Olga Kazakova
- National Physical Laboratory (NPL) , Teddington TW11 0LW , United Kingdom
| | - Hiroki Hibino
- School of Science and Technology , Kwansei Gakuin University , Hyogo 669-1337 , Japan
| | - Kazu Suenaga
- National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba 305-8565 , Japan
| | - Hiroki Ago
- Interdisciplinary Graduate School of Engineering Sciences , Kyushu University , Fukuoka 816-8580 , Japan
- National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba 305-8565 , Japan
- Global Innovation Center (GIC) , Kyushu University , Fukuoka 816-8580 , Japan
| |
Collapse
|
36
|
Zhuang Y, Zhao M, He Y, Cheng F, Chen S. Fabrication of ZnO/rGO/PPy heterostructure for electrochemical detection of mercury ion. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2018.08.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
37
|
Whelan PR, Panchal V, Petersen DH, Mackenzie DMA, Melios C, Pasternak I, Gallop J, Østerberg FW, U Jepsen P, Strupinski W, Kazakova O, Bøggild P. Electrical Homogeneity Mapping of Epitaxial Graphene on Silicon Carbide. ACS APPLIED MATERIALS & INTERFACES 2018; 10:31641-31647. [PMID: 30130090 DOI: 10.1021/acsami.8b11428] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Epitaxial graphene is a promising route to wafer-scale production of electronic graphene devices. Chemical vapor deposition of graphene on silicon carbide offers epitaxial growth with layer control but is subject to significant spatial and wafer-to-wafer variability. We use terahertz time-domain spectroscopy and micro four-point probes to analyze the spatial variations of quasi-freestanding bilayer graphene grown on 4 in. silicon carbide (SiC) wafers and find significant variations in electrical properties across large regions, which are even reproduced across graphene on different SiC wafers cut from the same ingot. The dc sheet conductivity of epitaxial graphene was found to vary more than 1 order of magnitude across a 4 in. SiC wafer. To determine the origin of the variations, we compare different optical and scanning probe microscopies with the electrical measurements from nano- to millimeter scale and identify three distinct qualities of graphene, which can be attributed to the microstructure of the SiC surface.
Collapse
Affiliation(s)
- Patrick R Whelan
- DTU Fotonik , Technical University of Denmark , Ørsteds Plads 343 , DK-2800 Kongens Lyngby , Denmark
| | - Vishal Panchal
- National Physical Laboratory , Hampton Road , Teddington TW11 0LW , U.K
| | | | | | - Christos Melios
- National Physical Laboratory , Hampton Road , Teddington TW11 0LW , U.K
| | - Iwona Pasternak
- Faculty of Physics , Warsaw University of Technology , Koszykowa 75 , 00-662 Warsaw , Poland
| | - John Gallop
- National Physical Laboratory , Hampton Road , Teddington TW11 0LW , U.K
| | | | - Peter U Jepsen
- DTU Fotonik , Technical University of Denmark , Ørsteds Plads 343 , DK-2800 Kongens Lyngby , Denmark
| | - Wlodek Strupinski
- Faculty of Physics , Warsaw University of Technology , Koszykowa 75 , 00-662 Warsaw , Poland
| | - Olga Kazakova
- National Physical Laboratory , Hampton Road , Teddington TW11 0LW , U.K
| | | |
Collapse
|
38
|
Dey A, Krishnamurthy S, Bowen J, Nordlund D, Meyyappan M, Gandhiraman RP. Plasma Jet Printing and in Situ Reduction of Highly Acidic Graphene Oxide. ACS NANO 2018; 12:5473-5481. [PMID: 29775279 DOI: 10.1021/acsnano.8b00903] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Miniaturization of electronic devices and the advancement of Internet of Things pose exciting challenges to develop technologies for patterned deposition of functional nanomaterials. Printed and flexible electronic devices and energy storage devices can be embedded onto clothing or other flexible surfaces. Graphene oxide (GO) has gained much attention in printed electronics due its solution processability, robustness, and high electrical conductivity in the reduced state. Here, we introduce an approach to print GO films from highly acidic suspensions with in situ reduction using an atmospheric pressure plasma jet. Low-temperature plasma of a He and H2 mixture was used successfully to reduce a highly acidic GO suspension (pH < 2) in situ during deposition. This technique overcomes the multiple intermediate steps required to increase the conductivity of deposited GO. X-ray spectroscopic studies confirmed that the reaction intermediates and the concentration of oxygen functionalities bonded to GO have been reduced significantly by this approach without any additional steps. Moreover, the reduced GO films showed enhanced conductivity. Hence, this technique has a strong potential for printing conducting patterns of GO for a range of large-scale applications.
Collapse
Affiliation(s)
- Avishek Dey
- School of Engineering and Innovation , The Open University , Milton Keynes MK7 6AA , United Kingdom
- NASA Ames Research Center , Moffett Field , California 94035 , United States
- Universities Space Research Association , Mountain View , California 94043 , United States
| | - Satheesh Krishnamurthy
- School of Engineering and Innovation , The Open University , Milton Keynes MK7 6AA , United Kingdom
| | - James Bowen
- School of Engineering and Innovation , The Open University , Milton Keynes MK7 6AA , United Kingdom
| | - Dennis Nordlund
- SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - M Meyyappan
- NASA Ames Research Center , Moffett Field , California 94035 , United States
| | - Ram P Gandhiraman
- NASA Ames Research Center , Moffett Field , California 94035 , United States
- Universities Space Research Association , Mountain View , California 94043 , United States
| |
Collapse
|
39
|
Amrania H, Drummond L, Coombes RC, Shousha S, Woodley-Barker L, Weir K, Hart W, Carter I, Phillips CC. New IR imaging modalities for cancer detection and for intra-cell chemical mapping with a sub-diffraction mid-IR s-SNOM. Faraday Discuss 2018; 187:539-53. [PMID: 27077445 DOI: 10.1039/c5fd00150a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present two new modalities for generating chemical maps. Both are mid-IR based and aimed at the biomedical community, but they differ substantially in their technological readiness. The first, so-called "Digistain", is a technologically mature "locked down" way of acquiring diffraction-limited chemical images of human cancer biopsy tissue. Although it is less flexible than conventional methods of acquiring IR images, this is an intentional, and key, design feature. It allows it to be used, on a routine basis, by clinical personnel themselves. It is in the process of a full clinical evaluation and the philosophy behind the approach is discussed. The second modality is a very new, probe-based "s-SNOM", which we are developing in conjunction with a new family of tunable "Quantum Cascade Laser" (QCL) diode lasers. Although in its infancy, this instrument can already deliver ultra-detailed chemical images whose spatial resolutions beat the normal diffraction limit by a factor of ∼1000. This is easily enough to generate chemical maps of the insides of single cells for the first time, and a range of new possible scientific applications are explored.
Collapse
Affiliation(s)
- H Amrania
- Physics Dept., Imperial College, London, SW7 2AZ, UK.
| | - L Drummond
- Physics Dept., Imperial College, London, SW7 2AZ, UK.
| | - R C Coombes
- Department of Cancer and Surgery, Faculty of Medicine, ICTEM, Room 145, Du Cane Road, London W12 0NN, UK
| | - S Shousha
- Department of Cancer and Surgery, Faculty of Medicine, ICTEM, Room 145, Du Cane Road, London W12 0NN, UK
| | - L Woodley-Barker
- Department of Cancer and Surgery, Faculty of Medicine, ICTEM, Room 145, Du Cane Road, London W12 0NN, UK
| | - K Weir
- Physics Dept., Imperial College, London, SW7 2AZ, UK.
| | - W Hart
- Physics Dept., Imperial College, London, SW7 2AZ, UK.
| | - I Carter
- Physics Dept., Imperial College, London, SW7 2AZ, UK.
| | - C C Phillips
- Physics Dept., Imperial College, London, SW7 2AZ, UK.
| |
Collapse
|
40
|
Luchkin SY, Stevenson KJ. On the Origin of Extended Resolution in Kelvin Probe Force Microscopy with a Worn Tip Apex. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2018; 24:126-131. [PMID: 29618390 DOI: 10.1017/s1431927618000156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this work we analyzed the effect of the atomic force microscopy probe tip apex shape on Kelvin Probe Force Microscopy (KPFM) potential sensitivity and spatial resolution. It was found that modification of the apex shape from spherical to planar upon thinning of the conductive coating leads to enhanced apex contribution to the total electrostatic force between the probe and the sample. The effect results in extended potential sensitivity and spatial resolution of KPFM. Experimental results were supported by calculations.
Collapse
Affiliation(s)
- Sergey Y Luchkin
- Skolkovo Institute of Science and Technology,Nobel St. 3,Moscow 143026,Russian Federation
| | - Keith J Stevenson
- Skolkovo Institute of Science and Technology,Nobel St. 3,Moscow 143026,Russian Federation
| |
Collapse
|
41
|
Abstract
By combining optical imaging, Raman spectroscopy, kelvin probe force microscopy (KFPM), and photoemission electron microscopy (PEEM), we show that graphene’s layer orientation, as well as layer thickness, measurably changes the surface potential (Φ). Detailed mapping of variable-thickness, rotationally-faulted graphene films allows us to correlate Φ with specific morphological features. Using KPFM and PEEM we measure ΔΦ up to 39 mV for layers with different twist angles, while ΔΦ ranges from 36–129 mV for different layer thicknesses. The surface potential between different twist angles or layer thicknesses is measured at the KPFM instrument resolution of ≤ 200 nm. The PEEM measured work function of 4.4 eV for graphene is consistent with doping levels on the order of 1012cm−2. We find that Φ scales linearly with Raman G-peak wavenumber shift (slope = 22.2 mV/cm−1) for all layers and twist angles, which is consistent with doping-dependent changes to graphene’s Fermi energy in the ‘high’ doping limit. Our results here emphasize that layer orientation is equally important as layer thickness when designing multilayer two-dimensional systems where surface potential is considered.
Collapse
|
42
|
Panchal V, Yang Y, Cheng G, Hu J, Kruskopf M, Liu CI, Rigosi AF, Melios C, Hight Walker AR, Newell DB, Kazakova O, Elmquist RE. Confocal laser scanning microscopy for rapid optical characterization of graphene. COMMUNICATIONS PHYSICS 2018; 1:10.1038/s42005-018-0084-6. [PMID: 31093580 PMCID: PMC6512973 DOI: 10.1038/s42005-018-0084-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 10/16/2018] [Indexed: 05/29/2023]
Abstract
Two-dimensional (2D) materials such as graphene have become the focus of extensive research efforts in condensed matter physics. They provide opportunities for both fundamental research and applications across a wide range of industries. Ideally, characterization of graphene requires non-invasive techniques with single-atomic-layer thickness resolution and nanometer lateral resolution. Moreover, commercial application of graphene requires fast and large-area scanning capability. We demonstrate the optimized balance of image resolution and acquisition time of non-invasive confocal laser scanning microscopy (CLSM), rendering it an indispensable tool for rapid analysis of mass-produced graphene. It is powerful for analysis of 1-5 layers of exfoliated graphene on Si/SiO2, and allows us to distinguish the interfacial layer and 1-3 layers of epitaxial graphene on SiC substrates. Furthermore, CLSM shows excellent correlation with conventional optical microscopy, atomic force microscopy, Kelvin probe force microscopy, conductive atomic force microscopy, scanning electron microscopy and Raman mapping.
Collapse
Affiliation(s)
- Vishal Panchal
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Yanfei Yang
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Joint Quantum Institute, University of Maryland, College Park, MD 20742, USA
| | - Guangjun Cheng
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Jiuning Hu
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Mattias Kruskopf
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Chieh-I Liu
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan
| | - Albert F Rigosi
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Christos Melios
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK
| | | | - David B Newell
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Olga Kazakova
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK
| | | |
Collapse
|
43
|
Jobst J, Kautz J, Mytiliniou M, Tromp RM, van der Molen SJ. Reprint of Low-energy electron potentiometry. Ultramicroscopy 2017; 183:8-14. [PMID: 29103783 DOI: 10.1016/j.ultramic.2017.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 04/21/2017] [Accepted: 05/09/2017] [Indexed: 11/28/2022]
Abstract
In a lot of systems, charge transport is governed by local features rather than being a global property as suggested by extracting a single resistance value. Consequently, techniques that resolve local structure in the electronic potential are crucial for a detailed understanding of electronic transport in realistic devices. Recently, we have introduced a new potentiometry method based on low-energy electron microscopy (LEEM) that utilizes characteristic features in the reflectivity spectra of layered materials [1]. Performing potentiometry experiments in LEEM has the advantage of being fast, offering a large field of view and the option to zoom in and out easily, and of being non-invasive compared to scanning-probe methods. However, not all materials show clear features in their reflectivity spectra. Here we, therefore, focus on a different version of low-energy electron potentiometry (LEEP) that uses the mirror mode transition, i.e. the drop in electron reflectivity around zero electron landing energy when they start to interact with the sample rather than being reflected in front of it. This transition is universal and sensitive to the local electrostatic surface potential (either workfunction or applied potential). It can consequently be used to perform LEEP experiments on a broader range of material compared to the method described in Ref[1]. We provide a detailed description of the experimental setup and demonstrate LEEP on workfunction-related intrinsic potential variations on the Si(111) surface and for a metal-semiconductor-metal junction with external bias applied. In the latter, we visualize the Schottky effect at the metal-semiconductor interface. Finally, we compare how robust the two LEEP techniques discussed above are against image distortions due to sample inhomogeneities or contamination.
Collapse
Affiliation(s)
- Johannes Jobst
- Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands; Department of Physics, Columbia University, New York, New York 10027, USA.
| | - Jaap Kautz
- Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands
| | - Maria Mytiliniou
- Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands
| | - Rudolf M Tromp
- Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands; IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, P.O. Box 218, USA
| | - Sense Jan van der Molen
- Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands
| |
Collapse
|
44
|
Ciro J, Mesa S, Montoya JF, Uribe JI, Betancur R, Jaramillo F. Simultaneous Top and Bottom Perovskite Interface Engineering by Fullerene Surface Modification of Titanium Dioxide as Electron Transport Layer. ACS APPLIED MATERIALS & INTERFACES 2017; 9:29654-29659. [PMID: 28805366 DOI: 10.1021/acsami.7b06343] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Optimization of the interface between the electron transport layer (ETL) and the hybrid perovskite is crucial to achieve high-performance perovskite solar cell (PSC) devices. Fullerene-based compounds have attracted attention as modifiers on the surface properties of TiO2, the archetypal ETL in regular n-i-p PSCs. However, the partial solubility of fullerenes in the aprotic solvents used for perovskite deposition hinders its application to low-temperature solution-processed PSCs. In this work, we introduce a new method for fullerene modification of TiO2 layers derived from nanoparticles (NPs) inks. Atomic force microscopy characterization reveals that the resulting ETL is a network of TiO2-NPs interconnected by fullerenes. Interestingly, this surface modification enhances the bottom interface of the perovskite by improving the charge transfer as well as the top perovskite interface by reducing surface trap states enhancing the contact with the p-type buffer layer. As a result, rigid PSCs reached a 17.2% power conversion efficiency (PCE), while flexible PSCs exhibited a remarkable stabilized PCE of 12.2% demonstrating the potential application of this approach for further scale-up of PSC devices.
Collapse
Affiliation(s)
- John Ciro
- Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería and ‡Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia UdeA , Calle 70 No. 52-21, Medellín 050010, Colombia
| | - Santiago Mesa
- Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería and ‡Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia UdeA , Calle 70 No. 52-21, Medellín 050010, Colombia
| | - Juan Felipe Montoya
- Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería and ‡Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia UdeA , Calle 70 No. 52-21, Medellín 050010, Colombia
| | - José Ignacio Uribe
- Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería and ‡Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia UdeA , Calle 70 No. 52-21, Medellín 050010, Colombia
| | - Rafael Betancur
- Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería and ‡Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia UdeA , Calle 70 No. 52-21, Medellín 050010, Colombia
| | - Franklin Jaramillo
- Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería and ‡Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia UdeA , Calle 70 No. 52-21, Medellín 050010, Colombia
| |
Collapse
|
45
|
Ciro J, Mesa S, Uribe JI, Mejía-Escobar MA, Ramirez D, Montoya JF, Betancur R, Yoo HS, Park NG, Jaramillo F. Optimization of the Ag/PCBM interface by a rhodamine interlayer to enhance the efficiency and stability of perovskite solar cells. NANOSCALE 2017; 9:9440-9446. [PMID: 28660942 DOI: 10.1039/c7nr01678f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Effective control of the interface between the metal cathode and the electron transport layer (ETL) is critical for achieving high performance p-i-n planar heterojunction perovskite solar cells (PSCs). Several organic molecules have been explored as interlayers between the silver (Ag) electrode and the ETL for the improvement in the photovoltaic conversion efficiency (PCE) of p-i-n planar PSCs. However, the role of these organic molecules in the charge transfer at the metal/ETL interface and the chemical degradation processes of PSCs has not yet been fully understood. In this work, we systematically explore the effects of the interfacial modification of the Ag/ETL interface on PSCs using rhodamine 101 as a model molecule. By the insertion of rhodamine 101 as an interlayer between Ag and fullerene derivatives (PC60BM and PC70BM) ETLs improve the PCE as well as the stability of p-i-n planar PSCs. Atomic force microscopy (AFM) characterization reveals that rhodamine passivates the defects at the PCBM layer and reduces the band bending at the PCBM surface. In consequence, charge transfer from the PCBM towards the Ag electrode is enhanced leading to an increased fill factor (FF) resulting in a PCE up to 16.6%. Moreover, rhodamine acts as a permeation barrier hindering the penetration of moisture towards the perovskite layer as well as preventing the chemical interaction of perovskite with the Ag electrode. Interestingly, the work function of the metal cathode remains more stable due to the rhodamine incorporation. Consequently, a better alignment between the quasi-Fermi level of PCBM and the Ag work function is achieved minimizing the energy barrier for charge extraction. This work contributes to reveal the relevance of proper interfacial engineering at the metal-cathode/organic-semiconductor interface.
Collapse
Affiliation(s)
- John Ciro
- Centro de Investigación, Innovación y Desarrollo de Materiales - CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
|
47
|
Zheng Q, Shi B, Li Z, Wang ZL. Recent Progress on Piezoelectric and Triboelectric Energy Harvesters in Biomedical Systems. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2017; 4:1700029. [PMID: 28725529 PMCID: PMC5515112 DOI: 10.1002/advs.201700029] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 02/13/2017] [Indexed: 05/17/2023]
Abstract
Implantable medical devices (IMDs) have become indispensable medical tools for improving the quality of life and prolonging the patient's lifespan. The minimization and extension of lifetime are main challenges for the development of IMDs. Current innovative research on this topic is focused on internal charging using the energy generated by the physiological environment or natural body activity. To harvest biomechanical energy efficiently, piezoelectric and triboelectric energy harvesters with sophisticated structural and material design have been developed. Energy from body movement, muscle contraction/relaxation, cardiac/lung motions, and blood circulation is captured and used for powering medical devices. Other recent progress in this field includes using PENGs and TENGs for our cognition of the biological processes by biological pressure/strain sensing, or direct intervention of them for some special self-powered treatments. Future opportunities lie in the fabrication of intelligent, flexible, stretchable, and/or fully biodegradable self-powered medical systems for monitoring biological signals and treatment of various diseases in vitro and in vivo.
Collapse
Affiliation(s)
- Qiang Zheng
- Beijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesNational Center for Nanoscience and Technology (NCNST)Beijing100083P. R. China
| | - Bojing Shi
- Beijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesNational Center for Nanoscience and Technology (NCNST)Beijing100083P. R. China
| | - Zhou Li
- Beijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesNational Center for Nanoscience and Technology (NCNST)Beijing100083P. R. China
| | - Zhong Lin Wang
- School of Materials Science and Engineering Georgia Institute of TechnologyAtlantaGA30332
| |
Collapse
|
48
|
Feng Y, Zhang K, Li H, Wang F, Zhou B, Fang M, Wang W, Wei J, Wong HSP. In situ visualization and detection of surface potential variation of mono and multilayer MoS 2 under different humidities using Kelvin probe force microscopy. NANOTECHNOLOGY 2017; 28:295705. [PMID: 28664874 DOI: 10.1088/1361-6528/aa7183] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The surface potential (SP) variations in mono and multilayer molybdenum disulfide (MoS2) are visualized in situ and detected using Kelvin probe force microscopy (KPFM) in different humidity conditions for the first time. N-type doping, which originates from the SiO2 substrate, is discovered in the exfoliated MoS2 and is accompanied by a screening length of five layers. The influence of water, which serves as an environmental gating for MoS2, is investigated by controlling the relative humidities (RHs) in the environmental chamber. A monotonic decrease in the SP is observed when the threshold concentration is achieved. This corresponds to the Fermi level variation, which is dominated by different processes. The results also indicate that water adsorption could result in MoS2 p-type doping and provide compensation that partially counteracts the substrate effect. Under this condition, the interlayer screening effect is influenced because of the water dipole-induced electric field. Density functional theory calculations are performed to determine the band structure variations and the interactions between water molecules and between water molecules and the MoS2 surface in mono and trilayer MoS2 under different RHs. The calculations are in excellent agreement with the experimental results. We propose that in situ measurements of the SP using KPFM under different environmental regimes is a noninvasive and effective method to provide real-time visualization and detection of electronic property variations in two-dimensional materials.
Collapse
Affiliation(s)
- Yulin Feng
- School of Electrical and Electronic Engineering, Tianjin Key Laboratory of Film Electronic & Communication Devices, Tianjin University of Technology, Tianjin, 300384, People's Republic of China
| | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Jobst J, Kautz J, Mytiliniou M, Tromp RM, van der Molen SJ. Low-energy electron potentiometry. Ultramicroscopy 2017; 181:74-80. [PMID: 28527312 DOI: 10.1016/j.ultramic.2017.05.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 04/21/2017] [Accepted: 05/09/2017] [Indexed: 12/01/2022]
Abstract
In a lot of systems, charge transport is governed by local features rather than being a global property as suggested by extracting a single resistance value. Consequently, techniques that resolve local structure in the electronic potential are crucial for a detailed understanding of electronic transport in realistic devices. Recently, we have introduced a new potentiometry method based on low-energy electron microscopy (LEEM) that utilizes characteristic features in the reflectivity spectra of layered materials [1]. Performing potentiometry experiments in LEEM has the advantage of being fast, offering a large field of view and the option to zoom in and out easily, and of being non-invasive compared to scanning-probe methods. However, not all materials show clear features in their reflectivity spectra. Here we, therefore, focus on a different version of low-energy electron potentiometry (LEEP) that uses the mirror mode transition, i.e. the drop in electron reflectivity around zero electron landing energy when they start to interact with the sample rather than being reflected in front of it. This transition is universal and sensitive to the local electrostatic surface potential (either workfunction or applied potential). It can consequently be used to perform LEEP experiments on a broader range of material compared to the method described in Ref[1]. We provide a detailed description of the experimental setup and demonstrate LEEP on workfunction-related intrinsic potential variations on the Si(111) surface and for a metal-semiconductor-metal junction with external bias applied. In the latter, we visualize the Schottky effect at the metal-semiconductor interface. Finally, we compare how robust the two LEEP techniques discussed above are against image distortions due to sample inhomogeneities or contamination.
Collapse
Affiliation(s)
- Johannes Jobst
- Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands; Department of Physics, Columbia University, New York, New York 10027, USA.
| | - Jaap Kautz
- Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands
| | - Maria Mytiliniou
- Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands
| | - Rudolf M Tromp
- Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands; IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, P.O. Box 218, USA
| | - Sense Jan van der Molen
- Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands
| |
Collapse
|
50
|
Li F, Qi J, Xu M, Xiao J, Xu Y, Zhang X, Liu S, Zhang Y. Layer Dependence and Light Tuning Surface Potential of 2D MoS 2 on Various Substrates. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:1603103. [PMID: 28092427 DOI: 10.1002/smll.201603103] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/30/2016] [Indexed: 05/23/2023]
Abstract
Here surface potential of chemical vapor deposition (CVD) grown 2D MoS2 with various layers is reported, and the effect of adherent substrate and light illumination on surface potential of monolayer MoS2 are investigated. The surface potential of MoS2 on Si/SiO2 substrate decreases from 4.93 to 4.84 eV with the increase in the number of layer from 1 to 4 or more. Especially, the surface potentials of monolayer MoS2 are strongly dependent on its adherent substrate, which are determined to be 4.55, 4.88, 4.93, 5.10, and 5.50 eV on Ag, graphene, Si/SiO2 , Au, and Pt substrates, respectively. Light irradiation is introduced to tuning the surface potential of monolayer MoS2 , with the increase in light intensity, the surface potential of MoS2 on Si/SiO2 substrate decreases from 4.93 to 4.74 eV, while increases from 5.50 to 5.56 eV on Pt substrate. The I-V curves on vertical of monolayer MoS2 /Pt heterojunction show the decrease in current with the increase of light intensity, and Schottky barrier height at MoS2 /Pt junctions increases from 0.302 to 0.342 eV. The changed surface potential can be explained by trapped charges on surface, photoinduced carriers, charge transfer, and local electric field.
Collapse
Affiliation(s)
- Feng Li
- State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Municipal Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Junjie Qi
- State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Municipal Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Minxuan Xu
- State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Municipal Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Jiankun Xiao
- State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Municipal Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Yuliang Xu
- State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Municipal Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Xiankun Zhang
- State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Municipal Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Shuo Liu
- State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Municipal Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Yue Zhang
- State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Municipal Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| |
Collapse
|