1
|
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
|
2
|
Checa M, Fuhr AS, Sun C, Vasudevan R, Ziatdinov M, Ivanov I, Yun SJ, Xiao K, Sehirlioglu A, Kim Y, Sharma P, Kelley KP, Domingo N, Jesse S, Collins L. High-speed mapping of surface charge dynamics using sparse scanning Kelvin probe force microscopy. Nat Commun 2023; 14:7196. [PMID: 37938577 PMCID: PMC10632481 DOI: 10.1038/s41467-023-42583-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 10/15/2023] [Indexed: 11/09/2023] Open
Abstract
Unraveling local dynamic charge processes is vital for progress in diverse fields, from microelectronics to energy storage. This relies on the ability to map charge carrier motion across multiple length- and timescales and understanding how these processes interact with the inherent material heterogeneities. Towards addressing this challenge, we introduce high-speed sparse scanning Kelvin probe force microscopy, which combines sparse scanning and image reconstruction. This approach is shown to enable sub-second imaging (>3 frames per second) of nanoscale charge dynamics, representing several orders of magnitude improvement over traditional Kelvin probe force microscopy imaging rates. Bridging this improved spatiotemporal resolution with macroscale device measurements, we successfully visualize electrochemically mediated diffusion of mobile surface ions on a LaAlO3/SrTiO3 planar device. Such processes are known to impact band-alignment and charge-transfer dynamics at these heterointerfaces. Furthermore, we monitor the diffusion of oxygen vacancies at the single grain level in polycrystalline TiO2. Through temperature-dependent measurements, we identify a charge diffusion activation energy of 0.18 eV, in good agreement with previously reported values and confirmed by DFT calculations. Together, these findings highlight the effectiveness and versatility of our method in understanding ionic charge carrier motion in microelectronics or nanoscale material systems.
Collapse
Affiliation(s)
- Marti Checa
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Addis S Fuhr
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Changhyo Sun
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Rama Vasudevan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Maxim Ziatdinov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37923, USA
| | - Ilia Ivanov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Seok Joon Yun
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Department of Semiconductor, University of Ulsan, Ulsan, 44610, Korea
| | - Kai Xiao
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Alp Sehirlioglu
- Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Yunseok Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Pankaj Sharma
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Kyle P Kelley
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Neus Domingo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Stephen Jesse
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| |
Collapse
|
3
|
Liu Y, Vasudevan RK, Kelley KK, Kim D, Sharma Y, Ahmadi M, Kalinin SV, Ziatdinov M. Decoding the shift-invariant data: applications for band-excitation scanning probe microscopy
*. MACHINE LEARNING: SCIENCE AND TECHNOLOGY 2021. [DOI: 10.1088/2632-2153/ac28de] [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] Open
|
4
|
Liu Y, Borodinov N, Collins L, Ahmadi M, Kalinin SV, Ovchinnikova OS, Ievlev AV. Role of Decomposition Product Ions in Hysteretic Behavior of Metal Halide Perovskite. ACS NANO 2021; 15:9017-9026. [PMID: 33955732 DOI: 10.1021/acsnano.1c02097] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ion migration is one of the most debated mechanisms and credited with multiple observed phenomena and performance in metal halide perovskites (MHPs) semiconductor devices. However, to date, the migration of ions and their effects on MHPs are not still fully understood, largely due to a lack of direct observations of temporal ion migration. In this work, using direct observation of ion migration in-operando, we observe the hysteretic migration behavior of intrinsic ions (i.e., CH3NH3+ and I-) as well as reveal the migration behavior of CH3NH3+ decomposition ions. We find that CH3NH3+ decomposition products can be affected by light and accumulate at the interfaces under bias. These MHP decomposition products are tightly related to the device performance and stability. Complementary results of time-resolved Kelvin probe force microscopy (tr-KPFM) demonstrate a correlation between dynamics of these interfacial ions and charge carriers. Overall, we find that there are a number of mobile ions including CH3NH3+ decomposition products in MHPs that need to be taken into account when measuring MHP device responses (e.g., charge dynamics) and should be considered in future optimization studies of MHP semiconductor devices.
Collapse
Affiliation(s)
- Yongtao Liu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Nikolay Borodinov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Mahshid Ahmadi
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Sergei V Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Olga S Ovchinnikova
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Anton V Ievlev
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| |
Collapse
|
5
|
Collins L, Vasudevan RK, Sehirlioglu A. Visualizing Charge Transport and Nanoscale Electrochemistry by Hyperspectral Kelvin Probe Force Microscopy. ACS APPLIED MATERIALS & INTERFACES 2020; 12:33361-33369. [PMID: 32579328 DOI: 10.1021/acsami.0c06426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Charge-transport and electrochemical processes are heavily influenced by the local microstructure. Kelvin probe force microscopy (KPFM) is a widely used technique to map electrochemical potentials at the nanometer scale; however, it offers little information on local charge dynamics. Here, we implement a hyperspectral KPFM approach for spatially mapping bias-dependent charge dynamics in timescales ranging from the sub-millisecond to the second regime. As a proof of principle, we investigate the role mobile surface charges play in a three-unit-cell LaAlO3/SrTiO3 oxide heterostructure. We explore machine learning approaches to assist with visualization, pattern recognition, and interpretation of the information-rich data sets. Linear unmixing methods reveal hidden bias-dependent interfacial processes, most likely water splitting, which are essentially unnoticed by functional fitting of the dynamic response alone. Hyperspectral KPFM will be beneficial for investigating nanoscale charge transport and local reactivity in systems involving a possible combination of electronic, ionic, and electrochemical phenomena.
Collapse
Affiliation(s)
- Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, United States
| | - Rama K Vasudevan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, United States
| | - Alp Sehirlioglu
- Department of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| |
Collapse
|
6
|
Abstract
Measurement of the contact potential difference (CPD) and work functions of materials are important in analyzing their electronic structures and surface residual charges. Kelvin probe force microscopy (KPFM), an imaging technique of atomic force microscopy, has been widely used for surface potential and work function mapping at the nanoscale. However, the conventional KPFM variants are often limited in their spatial resolution to 30-100 nm under ambient conditions. The continuingly decreasing size and increasing complexity of photoactive materials and semiconductor devices will present future challenges in uncovering their nanometer-scale electrical properties through KPFM. Here, we introduce a KPFM technique based on the pulsed force mode of atomic force microscopy. Our technique, named pulsed force Kelvin Probe Force Microscopy (PF-KPFM), is a single-pass technique that utilizes the intrinsic Fermi level alignment between the AFM tip and the conductive sample without the need for an external oscillating voltage. Induced cantilever oscillations generated by a spontaneous redistribution of electrons between tip and sample are extracted and used to obtain the cantilever oscillation amplitude and to derive the surface potential. The spatial resolution of PF-KPFM is shown to be <10 nm under ambient conditions. The high spatial resolution surface potential mapping enables in situ determination of ohmic and nonohmic contacts between metals and semiconductors, mapping boundaries of ferroelectric domains of BaTiO3, as well as characterization of protein aggregates. High spatial resolution measurements with PF-KPFM will facilitate further studies directed at uncovering electrical properties for emerging photoactive materials, biological samples, and semiconductor devices.
Collapse
Affiliation(s)
- Devon S Jakob
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Haomin Wang
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Xiaoji G Xu
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| |
Collapse
|
7
|
Ahmadi M, Collins L, Higgins K, Kim D, Lukosi E, Kalinin SV. Spatially Resolved Carrier Dynamics at MAPbBr 3 Single Crystal-Electrode Interface. ACS APPLIED MATERIALS & INTERFACES 2019; 11:41551-41560. [PMID: 31595742 DOI: 10.1021/acsami.9b16287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Despite the rapid progress in organic-inorganic halide perovskites (OIHPs) for applications such as solar cells and detectors, knowledge of coupling between electronic and ionic charge carrier dynamics is so far limited. While the presence of dual-conduction channels is widely accepted, the precise physical mechanisms governing the impact of electronic (e.g. electrons and holes) and ionic conduction, especially interface phenomena, remain uncertain. The lack of understanding stems largely from the lack of appropriate tools to capture the electrochemical dynamics on the length scales of the local inhomogeneities present (e.g., interfaces, grain boundaries, space charge regions) and time scales over which the coupled dynamics take place. Here, we implement Kelvin probe force microscopy (KPFM) to explore the charge carrier dynamics at the methylammonium lead tribromide (MAPbBr3) single crystal-gold electrode interface. In this work, the temporal dynamics of the electric field and charge carrier distribution at the electrode interface is spatially visualized by time-resolved KPFM mapping. The results demonstrate an interplay of several phenomena, including charge injection, recombination, and ion migration, leading to an unbalanced charge dynamic at MAPbBr3 single crystal-electrode interface under forward and reverse bias conditions explaining the origin of the current-voltage hysteresis in these devices. We contrast the bias-assisted charge dynamics under both illuminated and dark conditions, providing a comprehensive picture of overall carrier dynamics and interface properties in a MAPbBr3 single crystal with lateral symmetric Au electrodes. Remarkably, illumination leads to the formation of a wider space charge region due to accumulation of negative charges (both electrons and halide ions) at the positive electrode, which can effectively screen the external electric field leading to lower charge extraction efficiency. The results suggest that the choice of contact or interfacial engineering can control the performance of OIHP devices without requiring modification of the material's bulk properties.
Collapse
Affiliation(s)
| | - Liam Collins
- Oak Ridge National Laboratory , Center for Nanophase Materials Sciences , Oak Ridge , Tennessee 37831 , United States
| | | | | | | | - Sergei V Kalinin
- Oak Ridge National Laboratory , Center for Nanophase Materials Sciences , Oak Ridge , Tennessee 37831 , United States
| |
Collapse
|
8
|
Kalinin SV, Dyck O, Balke N, Neumayer S, Tsai WY, Vasudevan R, Lingerfelt D, Ahmadi M, Ziatdinov M, McDowell MT, Strelcov E. Toward Electrochemical Studies on the Nanometer and Atomic Scales: Progress, Challenges, and Opportunities. ACS NANO 2019; 13:9735-9780. [PMID: 31433942 DOI: 10.1021/acsnano.9b02687] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electrochemical reactions and ionic transport underpin the operation of a broad range of devices and applications, from energy storage and conversion to information technologies, as well as biochemical processes, artificial muscles, and soft actuators. Understanding the mechanisms governing function of these applications requires probing local electrochemical phenomena on the relevant time and length scales. Here, we discuss the challenges and opportunities for extending electrochemical characterization probes to the nanometer and ultimately atomic scales, including challenges in down-scaling classical methods, the emergence of novel probes enabled by nanotechnology and based on emergent physics and chemistry of nanoscale systems, and the integration of local data into macroscopic models. Scanning probe microscopy (SPM) methods based on strain detection, potential detection, and hysteretic current measurements are discussed. We further compare SPM to electron beam probes and discuss the applicability of electron beam methods to probe local electrochemical behavior on the mesoscopic and atomic levels. Similar to a SPM tip, the electron beam can be used both for observing behavior and as an active electrode to induce reactions. We briefly discuss new challenges and opportunities for conducting fundamental scientific studies, matter patterning, and atomic manipulation arising in this context.
Collapse
Affiliation(s)
- Sergei V Kalinin
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Ondrej Dyck
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Nina Balke
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Sabine Neumayer
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Wan-Yu Tsai
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Rama Vasudevan
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - David Lingerfelt
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Mahshid Ahmadi
- Joint Institute for Advanced Materials, Department of Materials Science and Engineering , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - Maxim Ziatdinov
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Matthew T McDowell
- George W. Woodruff School of Mechanical Engineering and School of Materials Science and Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Evgheni Strelcov
- Institute for Research in Electronics and Applied Physics , University of Maryland , College Park , Maryland 20742 , United States
| |
Collapse
|
9
|
Li X, Ahmadi M, Collins L, Kalinin SV. Deconvolving distribution of relaxation times, resistances and inductance from electrochemical impedance spectroscopy via statistical model selection: Exploiting structural-sparsity regularization and data-driven parameter tuning. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.05.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
10
|
Kilpatrick JI, Collins L, Weber SAL, Rodriguez BJ. Quantitative comparison of closed-loop and dual harmonic Kelvin probe force microscopy techniques. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:123708. [PMID: 30599628 DOI: 10.1063/1.5025432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
Kelvin probe force microscopy (KPFM) is a widely used technique to map surface potentials at the nanometer scale. In traditional KPFM, a feedback loop regulates the DC bias applied between a sharp conductive probe and a sample to nullify the electrostatic force (closed-loop operation). In comparison, open-loop techniques such as dual harmonic KPFM (DH-KPFM) are simpler to implement, are less sensitive to artefacts, offer the unique ability to probe voltage sensitive materials, and operate in liquid environments. Here, we directly compare the two techniques in terms of their bandwidth and sensitivity to instrumentation artefacts. Furthermore, we introduce a new correction for traditional KPFM termed "setpoint correction," which allows us to obtain agreement between open and closed-loop techniques within 1%. Quantitative validation of DH-KPFM may lead to a wider adoption of open-loop KPFM techniques by the scanning probe community.
Collapse
Affiliation(s)
- Jason I Kilpatrick
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | | | - Brian J Rodriguez
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| |
Collapse
|
11
|
Collins L, Kilpatrick JI, Kalinin SV, Rodriguez BJ. Towards nanoscale electrical measurements in liquid by advanced KPFM techniques: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:086101. [PMID: 29990308 DOI: 10.1088/1361-6633/aab560] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Fundamental mechanisms of energy storage, corrosion, sensing, and multiple biological functionalities are directly coupled to electrical processes and ionic dynamics at solid-liquid interfaces. In many cases, these processes are spatially inhomogeneous taking place at grain boundaries, step edges, point defects, ion channels, etc and possess complex time and voltage dependent dynamics. This necessitates time-resolved and real-space probing of these phenomena. In this review, we discuss the applications of force-sensitive voltage modulated scanning probe microscopy (SPM) for probing electrical phenomena at solid-liquid interfaces. We first describe the working principles behind electrostatic and Kelvin probe force microscopies (EFM & KPFM) at the gas-solid interface, review the state of the art in advanced KPFM methods and developments to (i) overcome limitations of classical KPFM, (ii) expand the information accessible from KPFM, and (iii) extend KPFM operation to liquid environments. We briefly discuss the theoretical framework of electrical double layer (EDL) forces and dynamics, the implications and breakdown of classical EDL models for highly charged interfaces or under high ion concentrations, and describe recent modifications of the classical EDL theory relevant for understanding nanoscale electrical measurements at the solid-liquid interface. We further review the latest achievements in mapping surface charge, dielectric constants, and electrodynamic and electrochemical processes in liquids. Finally, we outline the key challenges and opportunities that exist in the field of nanoscale electrical measurements in liquid as well as providing a roadmap for the future development of liquid KPFM.
Collapse
Affiliation(s)
- Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America. Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | | | | | | |
Collapse
|
12
|
|
13
|
Kalinin SV, Kim Y, Fong DD, Morozovska AN. Surface-screening mechanisms in ferroelectric thin films and their effect on polarization dynamics and domain structures. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:036502. [PMID: 29368693 DOI: 10.1088/1361-6633/aa915a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
For over 70 years, ferroelectric materials have been one of the central research topics for condensed matter physics and material science, an interest driven both by fundamental science and applications. However, ferroelectric surfaces, the key component of ferroelectric films and nanostructures, still present a significant theoretical and even conceptual challenge. Indeed, stability of ferroelectric phase per se necessitates screening of polarization charge. At surfaces, this can lead to coupling between ferroelectric and semiconducting properties of material, or with surface (electro) chemistry, going well beyond classical models applicable for ferroelectric interfaces. In this review, we summarize recent studies of surface-screening phenomena in ferroelectrics. We provide a brief overview of the historical understanding of the physics of ferroelectric surfaces, and existing theoretical models that both introduce screening mechanisms and explore the relationship between screening and relevant aspects of ferroelectric functionalities starting from phase stability itself. Given that the majority of ferroelectrics exist in multiple-domain states, we focus on local studies of screening phenomena using scanning probe microscopy techniques. We discuss recent studies of static and dynamic phenomena on ferroelectric surfaces, as well as phenomena observed under lateral transport, light, chemical, and pressure stimuli. We also note that the need for ionic screening renders polarization switching a coupled physical-electrochemical process and discuss the non-trivial phenomena such as chaotic behavior during domain switching that stem from this.
Collapse
Affiliation(s)
- Sergei V Kalinin
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | | | | | | |
Collapse
|
14
|
Ding J, Balachandran J, Sang X, Guo W, Veith GM, Bridges CA, Rouleau CM, Poplawsky JD, Bassiri-Gharb N, Ganesh P, Unocic RR. Influence of Nonstoichiometry on Proton Conductivity in Thin-Film Yttrium-Doped Barium Zirconate. ACS APPLIED MATERIALS & INTERFACES 2018; 10:4816-4823. [PMID: 29322765 DOI: 10.1021/acsami.7b16900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Proton-conducting perovskites have been widely studied because of their potential application as solid electrolytes in intermediate temperature solid oxide fuel cells. Structural and chemical heterogeneities can develop during synthesis, device fabrication, or service, which can profoundly affect proton transport. Here, we use time-resolved Kelvin probe force microscopy, scanning transmission electron microscopy, atom probe tomography, and density functional theory calculations to intentionally introduce Ba-deficient planar and spherical defects and link the resultant atomic structure with proton transport behavior in both stoichiometric and nonstoichiometric epitaxial, yttrium-doped barium zirconate thin films. The defects were intentionally induced through high-temperature annealing treatment, while maintaining the epitaxial single crystalline structure of the films, with an overall relaxation in the atomic structure. The annealed samples showed smaller magnitudes of local lattice distortions because of the formation of proton polarons, thereby leading to decreased proton-trapping effect. This resulted in a decrease in the activation energy for proton transport, leading to faster proton transport.
Collapse
Affiliation(s)
- Jilai Ding
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Janakiraman Balachandran
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Xiahan Sang
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Wei Guo
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Gabriel M Veith
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Craig A Bridges
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Christopher M Rouleau
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Jonathan D Poplawsky
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Nazanin Bassiri-Gharb
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Panchapakesan Ganesh
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Raymond R Unocic
- Center for Nanophase Materials Sciences, §Material Science and Technology Division, and ∥Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and ⊥The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| |
Collapse
|
15
|
Ding J, Strelcov E, Bassiri-Gharb N. Effects of Microstructure on Electrochemical Reactivity and Conductivity in Nanostructured Ceria Thin Films. JOURNAL OF THE AMERICAN CERAMIC SOCIETY. AMERICAN CERAMIC SOCIETY 2018; 101:10.1111/jace.15183. [PMID: 38505649 PMCID: PMC10949040 DOI: 10.1111/jace.15183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
The proton conductivity in functional oxides is crucial in determining electrochemistry and transport phenomena in a number of applications such as catalytic devices and fuel cells. However, single characterization techniques are usually limited in detecting the ionic dynamics at the full range of environmental conditions. In this report, we probe and uncover the links between the microstructure of nanostructured ceria (NC) and parameters that govern its electrochemical reaction and proton transport, by coupling experimental data obtained with time-resolved Kelvin probe force microscopy (tr-KPFM), electrochemical impedance spectroscopy (EIS), and finite element analysis. It is found that surface morphology determines the water splitting rate and proton conductivity at 25 °C and wet conditions, where protons are mainly generated and transported within surface physisorbed water layers. However, at higher temperature (i.e., ≥125 °C) and dry conditions, when physisorbed water evaporates, grain size and crystallographic orientation become significant factors. Specifically, the proton generation rate is negatively correlated with the grain size, whereas proton diffusivity is facilitated by surface {111} planes and additional conduction pathways offered by cracks and open pores connected to the surface.
Collapse
Affiliation(s)
- Jilai Ding
- Department of Materials Science and Engineering, Georgia Institute
of Technology, Atlanta, GA 30332, United States
| | - Evgheni Strelcov
- Center for Nanoscale Science and Technology, National Institute of
Standards and Technology, Gaithersburg, MD 20899, United States
- Maryland NanoCenter, University of Maryland, College Park, MD 20742,
United States
| | - Nazanin Bassiri-Gharb
- Department of Materials Science and Engineering, Georgia Institute
of Technology, Atlanta, GA 30332, United States
- G. W. Woodruff School of Mechanical Engineering, Georgia Institute
of Technology, Atlanta, GA 30332, United States
| |
Collapse
|
16
|
Strelcov E, Ahmadi M, Kalinin SV. Nanoscale Transport Imaging of Active Lateral Devices: Static and Frequency Dependent Modes. KELVIN PROBE FORCE MICROSCOPY 2018. [DOI: 10.1007/978-3-319-75687-5_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
|
17
|
|
18
|
Kalinin SV, Strelcov E, Belianinov A, Somnath S, Vasudevan RK, Lingerfelt EJ, Archibald RK, Chen C, Proksch R, Laanait N, Jesse S. Big, Deep, and Smart Data in Scanning Probe Microscopy. ACS NANO 2016; 10:9068-9086. [PMID: 27676453 DOI: 10.1021/acsnano.6b04212] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Scanning probe microscopy (SPM) techniques have opened the door to nanoscience and nanotechnology by enabling imaging and manipulation of the structure and functionality of matter at nanometer and atomic scales. Here, we analyze the scientific discovery process in SPM by following the information flow from the tip-surface junction, to knowledge adoption by the wider scientific community. We further discuss the challenges and opportunities offered by merging SPM with advanced data mining, visual analytics, and knowledge discovery technologies.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Chaomei Chen
- College of Computing and Informatics, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Roger Proksch
- Asylum Research, an Oxford Instruments Company , Santa Barbara, California 93117, United States
| | | | | |
Collapse
|
19
|
Ding J, Strelcov E, Kalinin SV, Bassiri-Gharb N. Electrochemical reactivity and proton transport mechanisms in nanostructured ceria. NANOTECHNOLOGY 2016; 27:345401. [PMID: 27407076 DOI: 10.1088/0957-4484/27/34/345401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electrochemical reactivity and ionic transport at the nanoscale are essential in many energy applications. In this study, time-resolved Kelvin probe force microscopy (tr-KPFM) is utilized for surface potential mapping of nanostructured ceria, in both space and time domains. The fundamental mechanisms of proton injection and transport are studied as a function of environmental conditions and the presence or absence of triple phase boundaries. Finite element modeling is used to extract physical parameters from the experimental data, allowing not only quantification of the observed processes, but also decoupling of their contributions to the measured signal. The constructed phase diagrams of the parameters demonstrate a thermally activated proton injection reaction at the triple phase boundary, and two transport processes that are responsible for the low-temperature proton conductivity of nanostructured ceria.
Collapse
Affiliation(s)
- J Ding
- Department of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | | | | | |
Collapse
|
20
|
Collins L, Belianinov A, Somnath S, Balke N, Kalinin SV, Jesse S. Full data acquisition in Kelvin Probe Force Microscopy: Mapping dynamic electric phenomena in real space. Sci Rep 2016; 6:30557. [PMID: 27514987 PMCID: PMC4981877 DOI: 10.1038/srep30557] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/22/2016] [Indexed: 12/17/2022] Open
Abstract
Kelvin probe force microscopy (KPFM) has provided deep insights into the local electronic, ionic and electrochemical functionalities in a broad range of materials and devices. In classical KPFM, which utilizes heterodyne detection and closed loop bias feedback, the cantilever response is down-sampled to a single measurement of the contact potential difference (CPD) per pixel. This level of detail, however, is insufficient for materials and devices involving bias and time dependent electrochemical events; or at solid-liquid interfaces, where non-linear or lossy dielectrics are present. Here, we demonstrate direct recovery of the bias dependence of the electrostatic force at high temporal resolution using General acquisition Mode (G-Mode) KPFM. G-Mode KPFM utilizes high speed detection, compression, and storage of the raw cantilever deflection signal in its entirety at high sampling rates. We show how G-Mode KPFM can be used to capture nanoscale CPD and capacitance information with a temporal resolution much faster than the cantilever bandwidth, determined by the modulation frequency of the AC voltage. In this way, G-Mode KPFM offers a new paradigm to study dynamic electric phenomena in electroactive interfaces as well as a promising route to extend KPFM to the solid-liquid interface.
Collapse
Affiliation(s)
- Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Alex Belianinov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Suhas Somnath
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Nina Balke
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Sergei V Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Stephen Jesse
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| |
Collapse
|
21
|
Strelcov E, Yang SM, Jesse S, Balke N, Vasudevan RK, Kalinin SV. Solid-state electrochemistry on the nanometer and atomic scales: the scanning probe microscopy approach. NANOSCALE 2016; 8:13838-58. [PMID: 27146961 PMCID: PMC5125544 DOI: 10.1039/c6nr01524g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Energy technologies of the 21(st) century require an understanding and precise control over ion transport and electrochemistry at all length scales - from single atoms to macroscopic devices. This short review provides a summary of recent studies dedicated to methods of advanced scanning probe microscopy for probing electrochemical transformations in solids at the meso-, nano- and atomic scales. The discussion presents the advantages and limitations of several techniques and a wealth of examples highlighting peculiarities of nanoscale electrochemistry.
Collapse
Affiliation(s)
- Evgheni Strelcov
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Maryland Nanocenter, University of Maryland, College Park, MD 20742
| | - Sang Mo Yang
- The Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, TN 37831
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Stephen Jesse
- The Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, TN 37831
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Nina Balke
- The Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, TN 37831
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Rama K. Vasudevan
- The Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, TN 37831
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Sergei V. Kalinin
- The Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, TN 37831
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| |
Collapse
|
22
|
Collins L, Belianinov A, Somnath S, Rodriguez BJ, Balke N, Kalinin SV, Jesse S. Multifrequency spectrum analysis using fully digital G Mode-Kelvin probe force microscopy. NANOTECHNOLOGY 2016; 27:105706. [PMID: 26866505 DOI: 10.1088/0957-4484/27/10/105706] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Since its inception over two decades ago, Kelvin probe force microscopy (KPFM) has become the standard technique for characterizing electrostatic, electrochemical and electronic properties at the nanoscale. In this work, we present a purely digital, software-based approach to KPFM utilizing big data acquisition and analysis methods. General mode (G-Mode) KPFM works by capturing the entire photodetector data stream, typically at the sampling rate limit, followed by subsequent de-noising, analysis and compression of the cantilever response. We demonstrate that the G-Mode approach allows simultaneous multi-harmonic detection, combined with on-the-fly transfer function correction-required for quantitative CPD mapping. The KPFM approach outlined in this work significantly simplifies the technique by avoiding cumbersome instrumentation optimization steps (i.e. lock in parameters, feedback gains etc), while also retaining the flexibility to be implemented on any atomic force microscopy platform. We demonstrate the added advantages of G-Mode KPFM by allowing simultaneous mapping of CPD and capacitance gradient (C') channels as well as increased flexibility in data exploration across frequency, time, space, and noise domains. G-Mode KPFM is particularly suitable for characterizing voltage sensitive materials or for operation in conductive electrolytes, and will be useful for probing electrodynamics in photovoltaics, liquids and ionic conductors.
Collapse
Affiliation(s)
- Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | | | | | | | | | | | | |
Collapse
|
23
|
Ding J, Strelcov E, Kalinin SV, Bassiri-Gharb N. Spatially Resolved Probing of Electrochemical Reactions via Energy Discovery Platforms. NANO LETTERS 2015; 15:3669-3676. [PMID: 26027805 DOI: 10.1021/acs.nanolett.5b01613] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The electrochemical reactivity of solid surfaces underpins functionality of a broad spectrum of materials and devices ranging from energy storage and conversion, to sensors and catalytic devices. The surface electrochemistry is, however, a complex process, controlled by the interplay of charge generation, field-controlled and diffusion-controlled transport. Here we explore the fundamental mechanisms of electrochemical reactivity on nanocrystalline ceria, using the synergy of nanofabricated devices and time-resolved Kelvin probe force microscopy (tr-KPFM), an approach we refer to as energy discovery platform. Through tr-KPFM, the surface potential mapping in both the space and time domains and current variation over time are obtained, enabling analysis of local ionic and electronic transport and their dynamic behavior on the 10 ms to 10 s scale. Based on their different responses in the time domain, conduction mechanisms can be separated and identified in a variety of environmental conditions, such as humidity and temperature. The theoretical modeling of ion transport through finite element method allows for creation of a minimal model consistent with observed phenomena, and establishing of the dynamic characteristics of the process, including mobility and diffusivity of charged species. The future potential of the energy discovery platforms is also discussed.
Collapse
Affiliation(s)
- Jilai Ding
- †School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Evgheni Strelcov
- ‡Institute for Functional Imaging of Materials and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sergei V Kalinin
- ‡Institute for Functional Imaging of Materials and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Nazanin Bassiri-Gharb
- †School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- §G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| |
Collapse
|
24
|
Strelcov E, Ievlev AV, Jesse S, Kravchenko II, Shur VY, Kalinin SV. Direct probing of charge injection and polarization-controlled ionic mobility on ferroelectric LiNbO(3) surfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:958-63. [PMID: 24277472 DOI: 10.1002/adma.201304002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 08/26/2013] [Indexed: 05/14/2023]
Abstract
Mapping surface potential with time-resolved Kelvin probe force microscopy (tr-KPFM) in LiNbO3 periodically poled single crystals reveals activation of the surface ionic subsystem. Electric fields of certain strength induce injection of charge, formation of an active region in its vicinity and uneven distribution of screening charge on the opposite ferroelectric domains. Tr-KPFM technique allows investigating these phenomena in details.
Collapse
Affiliation(s)
- Evgheni Strelcov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, United States
| | | | | | | | | | | |
Collapse
|
25
|
Collins L, Kilpatrick JI, Weber SAL, Tselev A, Vlassiouk IV, Ivanov IN, Jesse S, Kalinin SV, Rodriguez BJ. Open loop Kelvin probe force microscopy with single and multi-frequency excitation. NANOTECHNOLOGY 2013; 24:475702. [PMID: 24176878 DOI: 10.1088/0957-4484/24/47/475702] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Conventional Kelvin probe force microscopy (KPFM) relies on closed loop (CL) bias feedback for the determination of surface potential (SP). However, SP measured by CL-KPFM has been shown to be strongly influenced by the choice of measurement parameters due to non-electrostatic contributions to the input signal of the bias feedback loop. This often leads to systematic errors of several hundred mV and can also result in topographical crosstalk. Here, open loop (OL)-KPFM modes are investigated as a means of obtaining a quantitative, crosstalk free measurement of the SP of graphene grown on Cu foil, and are directly contrasted with CL-KPFM. OL-KPFM operation is demonstrated in both single and multi-frequency excitation regimes, yielding quantitative SP measurements. The SP difference between single and multilayer graphene structures using OL-KPFM was found to be 63 ± 11 mV, consistent with values previously reported by CL-KPFM. Furthermore, the same relative potential difference between Al2O3-coated graphene and Al2O3-coated Cu was observed using both CL and OL techniques. We observed an offset of 55 mV between absolute SP values obtained by OL and CL techniques, which is attributed to the influence of non-electrostatic contributions to the input of the bias feedback used in CL-KPFM.
Collapse
Affiliation(s)
- L Collins
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland. Conway Institute of Biomedical and Biomolecular Research, University College Dublin, Belfield, Dublin 4, Ireland
| | | | | | | | | | | | | | | | | |
Collapse
|