1
|
Callaghan PJ, Caffrey D, Zhussupbekov K, Berman S, Zhussupbekova A, Smith CM, Shvets IV. Variation in the Bandgap of Amorphous Zinc Tin Oxide: Investigating the Thickness Dependence via In Situ STS. ACS Omega 2024; 9:7262-7268. [PMID: 38371851 PMCID: PMC10870296 DOI: 10.1021/acsomega.3c09958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/13/2024] [Accepted: 01/18/2024] [Indexed: 02/20/2024]
Abstract
Amorphous transparent conducting oxides (a-TCOs) have seen substantial interest in recent years due to the significant benefits that they can bring to transparent electronic devices. One such material of promise is amorphous ZnxSn1-xOy (a-ZTO). a-ZTO possesses many attractive properties for a TCO such as high transparency in the visible range, tunable charge carrier concentration, electron mobility, and only being composed of common and abundant elements. In this work, we employ a combination of UV-vis spectrophotometry, X-ray photoemission spectroscopy, and in situ scanning tunneling spectroscopy to investigate a 0.33 eV blue shift in the optical bandgap of a-ZTO, which we conclude to be due to quantum confinement effects.
Collapse
Affiliation(s)
- Peter J Callaghan
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - David Caffrey
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | | | - Samuel Berman
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Ainur Zhussupbekova
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- L.N. Gumilyov Eurasian National University, 2 Satpayev Street, Astana 010000, Kazakhstan
| | - Christopher M Smith
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Igor V Shvets
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| |
Collapse
|
2
|
Chekmazov SV, Ksenz AS, Ionov AM, Mazilkin AA, Smirnov AA, Pershina EA, Ryzhkin IA, Vilkov OY, Walls B, Zhussupbekov K, Shvets IV, Bozhko SI. The topological soliton in Peierls semimetal Sb. Sci Rep 2024; 14:2331. [PMID: 38281983 PMCID: PMC10822873 DOI: 10.1038/s41598-024-52411-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 01/18/2024] [Indexed: 01/30/2024] Open
Abstract
Sb is a three-dimensional Peierls insulator. The Peierls instability gives rise to doubling of the translational period along the [111] direction and alternating van der Waals and covalent bonding between (111) atomic planes. At the (111) surface of Sb, the Peierls condition is violated, which in theory can give rise to properties differing from the bulk. The atomic and electronic structure of the (111) surface of Sb have been simulated by density functional theory calculations. We have considered the two possible (111) surfaces, containing van der Waals dangling bonds or containing covalent dangling bonds. In the models, the surfaces are infinite and the structure is defect free. Structural optimization of the model containing covalent dangling bonds results in strong deformation, which is well described by a topological soliton within the Su-Schrieffer-Heeger model centered about 25 Å below the surface. The electronic states associated with the soliton see an increase in the density of states (DOS) at the Fermi level by around an order of magnitude at the soliton center. Scanning tunneling microscopy and spectroscopy (STM/STS) measurements reveal two distinct surface regions, indicating that there are different surface regions cleaving van der Waals and covalent bonds. The DFT is in good agreement with the STM/STS experiments.
Collapse
Affiliation(s)
| | - Andrei S Ksenz
- Institute of Solid State Physics, RAS, Chernogolovka, Russia
| | - Andrei M Ionov
- Institute of Solid State Physics, RAS, Chernogolovka, Russia
- School of Physics, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland
| | | | - Anton A Smirnov
- Institute of Solid State Physics, RAS, Chernogolovka, Russia
| | | | - Ivan A Ryzhkin
- Institute of Solid State Physics, RAS, Chernogolovka, Russia
| | - Oleg Yu Vilkov
- Saint Petersburg State University, Saint Petersburg, Russia
| | - Brian Walls
- School of Physics, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland.
| | - Kuanysh Zhussupbekov
- School of Physics, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland
| | - Igor V Shvets
- School of Physics, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland
| | - Sergey I Bozhko
- Institute of Solid State Physics, RAS, Chernogolovka, Russia
- School of Physics, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland
| |
Collapse
|
3
|
Parkhomenko I, Vlasukova L, Komarov F, Kovalchuk N, Demidovich S, Zhussupbekova A, Zhussupbekov K, Shvets IV, Milchanin O, Zhigulin D, Romanov I. Effect of Rapid Thermal Annealing on Si-Based Dielectric Films Grown by ICP-CVD. ACS Omega 2023; 8:30768-30775. [PMID: 37636914 PMCID: PMC10448691 DOI: 10.1021/acsomega.3c04997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 07/28/2023] [Indexed: 08/29/2023]
Abstract
Silicon nitride, silicon oxide, and silicon oxynitride thin films were deposited on the Si substrate by inductively coupled plasma chemical vapor deposition and annealed at 1100 °C for 3 min in an Ar environment. Silicon nitride and silicon oxide films deposited at ratios of the reactant flow rates of SiH4/N2 = 1.875 and SiH4/N2O = 3, respectively, were Si-rich, while Si excess for the oxynitride film (SiH4/N2/N2O = 3:2:2) was not found. Annealing resulted in a thickness decrease and structural transformation for SiOx and SiNx films. Nanocrystalline phases of Si as well as α- and β-Si3N4 were found in the annealed silicon nitride film. Compared to oxide and nitride films, the oxynitride film is the least susceptible to change during annealing. The relationship between the structure, composition, and optical properties of the Si-based films has been revealed. It has been shown that the calculated optical parameters (refractive index, extinction coefficient) reflect structural peculiarities of the as-deposited and annealed films.
Collapse
Affiliation(s)
- Irina Parkhomenko
- Belarusian
State University, Kurchatov Str. 5, 220045 Minsk, Belarus
| | | | - Fadei Komarov
- A.N.
Sevchenko Institute of Applied Physical Problems of Belarusian State
University, Kurchatov
Str. 7, 220045 Minsk, Belarus
| | - Nataliya Kovalchuk
- Joint
Stock Company “Integral”, Kazintsa Str. 121 A, 220108 Minsk, Belarus
| | - Sergey Demidovich
- Joint
Stock Company “Integral”, Kazintsa Str. 121 A, 220108 Minsk, Belarus
| | - Ainur Zhussupbekova
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin D02 PN40, Ireland
- L.N.
Gumilyov Eurasian National University, 2 Satpayev Street, Astana 010000, Kazakhstan
| | - Kuanysh Zhussupbekov
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin D02 PN40, Ireland
| | - Igor V. Shvets
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin D02 PN40, Ireland
| | - Oleg Milchanin
- A.N.
Sevchenko Institute of Applied Physical Problems of Belarusian State
University, Kurchatov
Str. 7, 220045 Minsk, Belarus
| | - Dmitry Zhigulin
- Joint
Stock Company “Integral”, Kazintsa Str. 121 A, 220108 Minsk, Belarus
| | - Ivan Romanov
- Belarusian
State University, Kurchatov Str. 5, 220045 Minsk, Belarus
| |
Collapse
|
4
|
Molkenova A, Serik L, Ramazanova A, Zhumanova K, Duisenbayeva B, Zhussupbekova A, Zhussupbekov K, Shvets IV, Kim KS, Han DW, Atabaev TS. Terbium-doped carbon dots (Tb-CDs) as a novel contrast agent for efficient X-ray attenuation. RSC Adv 2023; 13:14974-14979. [PMID: 37200699 PMCID: PMC10187046 DOI: 10.1039/d3ra00958k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 04/25/2023] [Indexed: 05/20/2023] Open
Abstract
Metal-doped carbon dots have attracted considerable attention in nanomedicine over the last decade owing to their high biocompatibility and great potential for bioimaging, photothermal therapy, and photodynamic therapy. In this study, we prepared, and for the first time, examined terbium-doped CDs (Tb-CDs) as a novel contrast agent for computed tomography. A detailed physicochemical analysis revealed that the prepared Tb-CDs have small sizes (∼2-3 nm), contain relatively high terbium concentration (∼13.3 wt%), and exhibit excellent aqueous colloidal stability. Furthermore, preliminary cell viability and CT measurements suggested that Tb-CDs exhibit negligible cytotoxicity toward L-929 cells and demonstrate high X-ray absorption performance (∼48.2 ± 3.9 HU L g-1). Based on these findings, the prepared Tb-CDs could serve as a promising contrast agent for efficient X-ray attenuation.
Collapse
Affiliation(s)
- Anara Molkenova
- Institute of Advanced Organic Materials, Pusan National University Busan 46241 Republic of Korea
| | - Lazzat Serik
- Department of Chemistry, Nazarbayev University Astana 010000 Kazakhstan
| | | | - Kamila Zhumanova
- Department of Chemistry, Nazarbayev University Astana 010000 Kazakhstan
| | - Bakyt Duisenbayeva
- Department of Radiology, Republican Diagnostic Center Astana 010000 Kazakhstan
| | - Ainur Zhussupbekova
- School of Physics, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin Dublin Ireland
| | - Kuanysh Zhussupbekov
- School of Physics, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin Dublin Ireland
| | - Igor V Shvets
- School of Physics, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin Dublin Ireland
| | - Ki Su Kim
- Institute of Advanced Organic Materials, Pusan National University Busan 46241 Republic of Korea
- School of Chemical Engineering, College of Engineering, Pusan National University 2 Busandaehak-ro 63beon-gil, Geumjeong-gu Busan 46241 Republic of Korea
- Department of Organic Material Science & Engineering, Pusan National University 2 Busandaehak-ro 63beon-gil, Geumjeong-gu Busan 46241 Republic of Korea
| | - Dong-Wook Han
- Department of Cogno-Mechatronics Engineering, Pusan National University Busan 46241 Republic of Korea
| | - Timur Sh Atabaev
- Department of Chemistry, Nazarbayev University Astana 010000 Kazakhstan
| |
Collapse
|
5
|
Walls B, Murtagh O, Bozhko SI, Ionov A, Mazilkin AA, Mullarkey D, Zhussupbekova A, Shulyatev DA, Zhussupbekov K, Andreev N, Tabachkova N, Shvets IV. VO x Phase Mixture of Reduced Single Crystalline V 2O 5: VO 2 Resistive Switching. Materials (Basel) 2022; 15:7652. [PMID: 36363246 PMCID: PMC9653758 DOI: 10.3390/ma15217652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
The strongly correlated electron material, vanadium dioxide (VO2), has seen considerable attention and research application in metal-oxide electronics due to its metal-to-insulator transition close to room temperature. Vacuum annealing a V2O5(010) single crystal results in Wadsley phases (VnO2n+1, n > 1) and VO2. The resistance changes by a factor of 20 at 342 K, corresponding to the metal-to-insulator phase transition of VO2. Macroscopic voltage-current measurements with a probe separation on the millimetre scale result in Joule heating-induced resistive switching at extremely low voltages of under a volt. This can reduce the hysteresis and facilitate low temperature operation of VO2 devices, of potential benefit for switching speed and device stability. This is correlated to the low resistance of the system at temperatures below the transition. High-resolution transmission electron microscopy measurements reveal a complex structural relationship between V2O5, VO2 and V6O13 crystallites. Percolation paths incorporating both VO2 and metallic V6O13 are revealed, which can reduce the resistance below the transition and result in exceptionally low voltage resistive switching.
Collapse
Affiliation(s)
- Brian Walls
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, D02PD91 Dublin, Ireland
| | - Oisín Murtagh
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, D02PD91 Dublin, Ireland
| | - Sergey I. Bozhko
- Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia
| | - Andrei Ionov
- Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia
- Faculty of Physics, Higher School of Economics University, Myasnitskaya Ulitsa, 20, 101000 Moscow, Russia
| | - Andrey A. Mazilkin
- Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia
| | - Daragh Mullarkey
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, D02PD91 Dublin, Ireland
| | - Ainur Zhussupbekova
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, D02PD91 Dublin, Ireland
| | - Dmitry A. Shulyatev
- Materials Modeling and Development Laboratory, National University of Science and Technology MISIS, Leninskii Pr. 4, 119991 Moscow, Russia
| | - Kuanysh Zhussupbekov
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, D02PD91 Dublin, Ireland
| | - Nikolai Andreev
- Materials Modeling and Development Laboratory, National University of Science and Technology MISIS, Leninskii Pr. 4, 119991 Moscow, Russia
| | - Nataliya Tabachkova
- Materials Modeling and Development Laboratory, National University of Science and Technology MISIS, Leninskii Pr. 4, 119991 Moscow, Russia
- Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilov Str. 38, 119991 Moscow, Russia
| | - Igor V. Shvets
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, D02PD91 Dublin, Ireland
| |
Collapse
|
6
|
Zhussupbekova A, Zhussupbekov K, Verre R, Caffrey D, Shiel K, Shvets IV, Fleischer K. An In Situ Study of Precursor Decomposition via Refractive Index Sensing in p-Type Transparent Copper Chromium Oxide. Chem Mater 2022; 34:3020-3027. [PMID: 35431441 PMCID: PMC9009087 DOI: 10.1021/acs.chemmater.1c03910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Oxide semiconductors are penetrating into a wide range of energy, environmental, and electronic applications, possessing a potential to outrun currently employed semiconductors. However, an insufficient development of p-type oxides is a major obstacle against complete oxide electronics. Quite often oxide deposition is performed by the spray pyrolysis method, inexpensive to implement and therefore accessible to a large number of laboratories. Although, the complex growth chemistry and a lack of in situ monitoring during the synthesis process can complicate the growth optimization of multicomponent oxides. Here we present a concept of plasmonic, optical sensing that has been applied to spray pyrolysis oxide film growth monitoring for the first time. The proposed method utilizes a polarization based refractive index sensing platform using Au nanodimers as transducing elements. As a proof of concept, the changes in the refractive index of the grown film were extracted from individual Cu(acac)2 and Cr(acac)3 precursors in real time to reveal their thermal decomposition processes. Obtained activation energies give insight into the physical origin of the narrow temperature window for the synthesis of high performing p-type transparent conducting copper chromium oxide Cu x CrO2. The versatility of the proposed method makes it effective in the growth rate monitoring of various oxides, exploring new candidate materials and optimizing the synthesis conditions for acquisition of high performing oxides synthesized by a high throughput cost-effective method.
Collapse
Affiliation(s)
- Ainur Zhussupbekova
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Kuanysh Zhussupbekov
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Ruggero Verre
- Department
of Physics, Chalmers University of Technology, Gothenburg 412 96, Sweden
| | - David Caffrey
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Kyle Shiel
- School
of Physics, Dublin City University, Dublin 9, Ireland
| | - Igor V. Shvets
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | | |
Collapse
|
7
|
Zhussupbekov K, Walshe K, Walls B, Ionov A, Bozhko SI, Ksenz A, Mozhchil RN, Zhussupbekova A, Fleischer K, Berman S, Zhilyaev I, O’Regan DD, Shvets IV. Surface Modification and Subsequent Fermi Density Enhancement of Bi(111). J Phys Chem C Nanomater Interfaces 2021; 125:5549-5558. [PMID: 34276852 PMCID: PMC8279637 DOI: 10.1021/acs.jpcc.0c07345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 02/24/2021] [Indexed: 06/13/2023]
Abstract
Defects introduced to the surface of Bi(111) break the translational symmetry and modify the surface states locally. We present a theoretical and experimental study of the 2D defects on the surface of Bi(111) and the states that they induce. Bi crystals cleaved in ultrahigh vacuum (UHV) at low temperature (110 K) and the resulting ion-etched surface are investigated by low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy (UPS), and scanning tunneling microscopy (STM) as well as spectroscopy (STS) techniques in combination with density functional theory (DFT) calculations. STS measurements of cleaved Bi(111) reveal that a commonly observed bilayer step edge has a lower density of states (DOS) around the Fermi level as compared to the atomic-flat terrace. Following ion bombardment, the Bi(111) surface reveals anomalous behavior at both 110 and 300 K: Surface periodicity is observed by LEED, and a significant increase in the number of bilayer step edges and energetically unfavorable monolayer steps is observed by STM. It is suggested that the newly exposed monolayer steps and the type A bilayer step edges result in an increase to the surface Fermi density as evidenced by UPS measurements and the Kohn-Sham DOS. These states appear to be thermodynamically stable under UHV conditions.
Collapse
Affiliation(s)
- Kuanysh Zhussupbekov
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Killian Walshe
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Brian Walls
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Andrei Ionov
- Institute
of Solid State Physics, Russian Academy
of Sciences, Chernogolovka, Russia
| | - Sergei I. Bozhko
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
- Institute
of Solid State Physics, Russian Academy
of Sciences, Chernogolovka, Russia
| | - Andrei Ksenz
- Institute
of Solid State Physics, Russian Academy
of Sciences, Chernogolovka, Russia
| | - Rais N. Mozhchil
- Institute
of Solid State Physics, Russian Academy
of Sciences, Chernogolovka, Russia
| | - Ainur Zhussupbekova
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Karsten Fleischer
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
- School
of Physical Sciences, Dublin City University, Dublin 9, Ireland
| | - Samuel Berman
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Ivan Zhilyaev
- Institute
of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences, Chernogolovka, Russia
| | - David D. O’Regan
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
- AMBER,
the SFI Research Centre for Advanced Materials and BioEngineering
Research, Dublin 2, Ireland
| | - Igor V. Shvets
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| |
Collapse
|
8
|
Frolov AS, Sánchez-Barriga J, Callaert C, Hadermann J, Fedorov AV, Usachov DY, Chaika AN, Walls BC, Zhussupbekov K, Shvets IV, Muntwiler M, Amati M, Gregoratti L, Varykhalov AY, Rader O, Yashina LV. Atomic and Electronic Structure of a Multidomain GeTe Crystal. ACS Nano 2020; 14:16576-16589. [PMID: 33136362 DOI: 10.1021/acsnano.0c05851] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Renewed interest in the ferroelectric semiconductor germanium telluride was recently triggered by the direct observation of a giant Rashba effect and a 30-year-old dream about a functional spin field-effect transistor. In this respect, all-electrical control of the spin texture in this material in combination with ferroelectric properties at the nanoscale would create advanced functionalities in spintronics and data information processing. Here, we investigate the atomic and electronic properties of GeTe bulk single crystals and their (111) surfaces. We succeeded in growing crystals possessing solely inversion domains of ∼10 nm thickness parallel to each other. Using HAADF-TEM we observe two types of domain boundaries, one of them being similar in structure to the van der Waals gap in layered materials. This structure is responsible for the formation of surface domains with preferential Te-termination (∼68%) as we determined using photoelectron diffraction and XPS. The lateral dimensions of the surface domains are in the range of ∼10-100 nm, and both Ge- and Te-terminations reveal no reconstruction. Using spin-ARPES we establish an intrinsic quantitative relationship between the spin polarization of pure bulk states and the relative contribution of different terminations, a result that is consistent with a reversal of the spin texture of the bulk Rashba bands for opposite configurations of the ferroelectric polarization within individual nanodomains. Our findings are important for potential applications of ferroelectric Rashba semiconductors in nonvolatile spintronic devices with advanced memory and computing capabilities at the nanoscale.
Collapse
Affiliation(s)
- Alexander S Frolov
- Department of Chemistry, Moscow State University, Leninskie Gory 1/3, 119991 Moscow, Russia
- Semenov Federal Research Center for Chemical Physics, Kosygina Street 4, 119991 Moscow, Russia
| | - Jaime Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY-II, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
| | - Carolien Callaert
- EMAT, Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Joke Hadermann
- EMAT, Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Alexander V Fedorov
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY-II, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
- IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany
- Joint Lab Functional Quantum Materials at BESSY-II, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
| | - Dmitry Yu Usachov
- St. Petersburg State University, 7/9 Universitetskaya nab., 199034 St. Petersburg, Russia
| | - Alexander N Chaika
- Institute of Solid State Physics RAS, Academician Ossipyan Street 2, Chernogolovka, 142432 Moscow District, Russia
| | - Brian C Walls
- CRANN, School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | | | - Igor V Shvets
- CRANN, School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - Matthias Muntwiler
- Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Matteo Amati
- Elettra-Sincrotrone Trieste S.C.p.A., Area Science Park, I-34012 Basovizza, Trieste, Italy
| | - Luca Gregoratti
- Elettra-Sincrotrone Trieste S.C.p.A., Area Science Park, I-34012 Basovizza, Trieste, Italy
| | - Andrei Yu Varykhalov
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY-II, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
| | - Oliver Rader
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY-II, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
| | - Lada V Yashina
- Department of Chemistry, Moscow State University, Leninskie Gory 1/3, 119991 Moscow, Russia
- Semenov Federal Research Center for Chemical Physics, Kosygina Street 4, 119991 Moscow, Russia
| |
Collapse
|
9
|
Zhussupbekov K, Cullen CP, Zhussupbekova A, Shvets IV, Duesberg GS, McEvoy N, Ó Coileáin C. Electronic and structural characterisation of polycrystalline platinum disulfide thin films. RSC Adv 2020; 10:42001-42007. [PMID: 35516737 PMCID: PMC9057923 DOI: 10.1039/d0ra07405e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/02/2020] [Indexed: 12/15/2022] Open
Abstract
We employ a combination of scanning tunnelling microscopy (STM) and scanning tunnelling spectroscopy (STS) to investigate the properties of layered PtS2, synthesised via thermally assisted conversion (TAC) of a metallic Pt thin film. STM measurements reveal the 1T crystal structure of PtS2, and the lattice constant is determined to be 3.58 ± 0.03 Å. STS allowed the electronic structure of individual PtS2 crystallites to be directly probed and a bandgap of ∼1.03 eV was determined for a 3.8 nm thick flake at liquid nitrogen temperature. These findings substantially expand understanding of the atomic and electronic structure of PtS2 and indicate that STM is a powerful tool capable of locally probing non-uniform polycrystalline films, such as those produced by TAC. Prior to STM/STS measurements the quality of synthesised TAC PtS2 was analysed by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. These results are of relevance to applications-focussed studies centred on PtS2 and may inform future efforts to optimise the synthesis conditions for thin film PtS2. Semiconducting thin-film polycrystalline PtS2 is characterised by atomically resolved scanning tunnelling microscopy and spectroscopy.![]()
Collapse
Affiliation(s)
- Kuanysh Zhussupbekov
- School of Physics, Trinity College Dublin Dublin 2 Ireland .,AMBER Centre, CRANN Institute, Trinity College Dublin Dublin 2 Ireland
| | - Conor P Cullen
- AMBER Centre, CRANN Institute, Trinity College Dublin Dublin 2 Ireland .,School of Chemistry, Trinity College Dublin Dublin 2 D02 PN40 Ireland
| | - Ainur Zhussupbekova
- School of Physics, Trinity College Dublin Dublin 2 Ireland .,AMBER Centre, CRANN Institute, Trinity College Dublin Dublin 2 Ireland
| | - Igor V Shvets
- School of Physics, Trinity College Dublin Dublin 2 Ireland .,AMBER Centre, CRANN Institute, Trinity College Dublin Dublin 2 Ireland
| | - Georg S Duesberg
- Institute of Physics, EIT 2, Faculty of Electrical Engineering and Information Technology, Universität der Bundeswehr München 85579 Neubiberg Germany
| | - Niall McEvoy
- AMBER Centre, CRANN Institute, Trinity College Dublin Dublin 2 Ireland .,School of Chemistry, Trinity College Dublin Dublin 2 D02 PN40 Ireland
| | - Cormac Ó Coileáin
- AMBER Centre, CRANN Institute, Trinity College Dublin Dublin 2 Ireland .,School of Chemistry, Trinity College Dublin Dublin 2 D02 PN40 Ireland
| |
Collapse
|
10
|
Zhussupbekova A, Caffrey D, Zhussupbekov K, Smith CM, Shvets IV, Fleischer K. Low-Cost, High-Performance Spray Pyrolysis-Grown Amorphous Zinc Tin Oxide: The Challenge of a Complex Growth Process. ACS Appl Mater Interfaces 2020; 12:46892-46899. [PMID: 32955846 DOI: 10.1021/acsami.0c12148] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Transparent conductive oxides (TCOs) are important materials for a wide range of optoelectronic devices. Amorphous zinc tin oxide (a-ZTO) is a TCO and one of the best nontoxic, low-cost replacements for more expensive amorphous indium-gallium-zinc oxide. Here, we employ spray pyrolysis (SP), an inexpensive and versatile chemical vapor deposition-based technique, to synthesize a-ZTO with an as-deposited conductivity of ≈300 S/cm-the highest value hitherto among the reported solution-processed films. Compositional analysis via X-ray photoelectron spectroscopy reveals a nonstoichiometric transfer of Zn and Sn from the dissolved precursors into the film, with the best electrical properties achieved at a film composition of xfilm = 0.38 ± 0.04 ((ZnO)x(SnO2)1-x (0 < x < 1)). The morphology of these films is compared to films synthesized by physical vapor deposition (PVD), and a strong correlation between morphology and electrical properties is revealed. The granular nature of the SP-grown films, which seems like a drawback at first glance, brings about the prospect of using a-ZTO in ink-jet-printed films from a nanoparticle suspension for the room-temperature deposition. Brief post-anneal cycles in N2 gas improve the conductivity of the films by means of grain boundary (GB) passivation.
Collapse
Affiliation(s)
- Ainur Zhussupbekova
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - David Caffrey
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Kuanysh Zhussupbekov
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Christopher M Smith
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Igor V Shvets
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Karsten Fleischer
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
- School of Physics, Dublin City University, Dublin 9, Ireland
| |
Collapse
|
11
|
Mc Manus JB, Horvath DV, Browne MP, Cullen CP, Cunningham G, Hallam T, Zhussupbekov K, Mullarkey D, Coileáin CÓ, Shvets IV, Pumera M, Duesberg GS, McEvoy N. Low-temperature synthesis and electrocatalytic application of large-area PtTe 2 thin films. Nanotechnology 2020; 31:375601. [PMID: 32498057 DOI: 10.1088/1361-6528/ab9973] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The synthesis of transition metal dichalcogenides (TMDs) has been a primary focus for 2D nanomaterial research over the last 10 years, however, only a small fraction of this research has been concentrated on transition metal ditellurides. In particular, nanoscale platinum ditelluride (PtTe2) has rarely been investigated, despite its potential applications in catalysis, photonics and spintronics. Of the reports published, the majority examine mechanically-exfoliated flakes from chemical vapor transport (CVT) grown crystals. This method produces high quality-crystals, ideal for fundamental studies. However, it is very resource intensive and difficult to scale up meaning there are significant obstacles to implementation in large-scale applications. In this report, the synthesis of thin films of PtTe2 through the reaction of solid-phase precursor films is described. This offers a production method for large-area, thickness-controlled PtTe2, potentially suitable for a number of applications. These polycrystalline PtTe2 films were grown at temperatures as low as 450 °C, significantly below the typical temperatures used in the CVT synthesis methods. Adjusting the growth parameters allowed the surface coverage and morphology of the films to be controlled. Analysis with scanning electron- and scanning tunneling microscopy indicated grain sizes of above 1 µm could be achieved, comparing favorably with typical values of ∼50 nm for polycrystalline films. To investigate their potential applicability, these films were examined as electrocatalysts for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). The films showed promising catalytic behavior, however, the PtTe2 was found to undergo chemical transformation to a substoichiometric chalcogenide compound under ORR conditions. This study shows while PtTe2 is stable and highly useful for in HER, this property does not apply to ORR, which undergoes a fundamentally different mechanism. This study broadens our knowledge on the electrocatalysis of TMDs.
Collapse
Affiliation(s)
- John B Mc Manus
- School of Chemistry, Trinity College Dublin, Dublin 2 D02 PN40, Ireland. AMBER Centre, CRANN Institute, Trinity College Dublin, Dublin 2 D02 PN40, Ireland
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Molkenova A, Khamkhash L, Zhussupbekova A, Zhussupbekov K, Sarsenov S, Taniguchi I, Shvets IV, Atabaev TS. Solution-Based Deposition of Transparent Eu-Doped Titanium Oxide Thin Films for Potential Security Labeling and UV Screening. Nanomaterials (Basel) 2020; 10:nano10061132. [PMID: 32521694 PMCID: PMC7353274 DOI: 10.3390/nano10061132] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 01/14/2023]
Abstract
Transparent titanium oxide thin films attract enormous attention from the scientific community because of their prominent properties, such as low-cost, chemical stability, and optical transparency in the visible region. In this study, we developed an easy and scalable solution-based process for the deposition of transparent TiOx thin films on glass substrates. We showed that the proposed method is also suitable for the fabrication of metal-doped TiOx thin films. As proof-of-the-concept, europium Eu(III) ions were introduced into TiOx film. A photoluminescence (PL) study revealed that Eu-doped TiOx thin films showed strong red luminescence associated with 5D0→7Fj relaxation transitions in Eu (III). We found that prepared TiOx thin films significantly reduce the transmittance of destructive UV radiation; a feature that can be useful for the protection of photovoltaic devices. In addition, transparent and luminescent TiOx thin films can be utilized for potential security labeling.
Collapse
Affiliation(s)
- Anara Molkenova
- Department of Chemistry, Nazarbayev University, Nur-Sultan 010000, Kazakhstan;
- Correspondence: (A.M.); (T.S.A.)
| | - Laura Khamkhash
- Core Facilities, Nazarbayev University, Nur-Sultan 010000, Kazakhstan;
| | - Ainur Zhussupbekova
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland; (A.Z.); (K.Z.); (I.V.S.)
| | - Kuanysh Zhussupbekov
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland; (A.Z.); (K.Z.); (I.V.S.)
| | - Sagyntay Sarsenov
- Department of Chemistry, Nazarbayev University, Nur-Sultan 010000, Kazakhstan;
| | - Izumi Taniguchi
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan;
| | - Igor V. Shvets
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland; (A.Z.); (K.Z.); (I.V.S.)
| | - Timur Sh. Atabaev
- Department of Chemistry, Nazarbayev University, Nur-Sultan 010000, Kazakhstan;
- Correspondence: (A.M.); (T.S.A.)
| |
Collapse
|
13
|
Aristov VY, Chaika AN, Molodtsova OV, Babenkov SV, Locatelli A, Menteş TO, Sala A, Potorochin D, Marchenko D, Murphy B, Walls B, Zhussupbekov K, Shvets IV. Layer-by-Layer Graphene Growth on β-SiC/Si(001). ACS Nano 2019; 13:526-535. [PMID: 30525448 DOI: 10.1021/acsnano.8b07237] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The mechanism of few-layer graphene growth on the technologically relevant cubic-SiC/Si(001) substrate is uncovered using high-resolution core-level and angle-resolved photoelectron spectroscopy, low-energy electron microscopy, and microspot low-energy electron diffraction. The thickness of the graphitic overlayer supported on the silicon carbide substrate and related changes in the surface structure are precisely controlled by monitoring the progress of the surface graphitization in situ during high-temperature graphene synthesis, using a combination of microspectroscopic techniques. The experimental data reveal gradual changes in the preferential graphene lattice orientations at the initial stages of the few-layer graphene growth on SiC(001) and can act as reference data for controllable growth of single-, double-, and triple-layer graphene on silicon carbide substrates.
Collapse
Affiliation(s)
- Victor Yu Aristov
- Deutsches Elektronen-Synchrotron DESY , Notkestrasse 85 , D-22607 Hamburg , Germany
- Institute of Solid State Physics of the Russian Academy of Sciences , 2 Academician Ossipyan Street , Chernogolovka , Moscow District 142432 , Russian Federation
| | - Alexander N Chaika
- Institute of Solid State Physics of the Russian Academy of Sciences , 2 Academician Ossipyan Street , Chernogolovka , Moscow District 142432 , Russian Federation
- CRANN, School of Physics , Trinity College Dublin , Dublin 2 , Ireland
| | - Olga V Molodtsova
- Deutsches Elektronen-Synchrotron DESY , Notkestrasse 85 , D-22607 Hamburg , Germany
- National Research University of Information Technologies, Mechanics and Optics , Kronverksky prospekt 49 , 197101 Saint Petersburg , Russian Federation
| | - Sergey V Babenkov
- Deutsches Elektronen-Synchrotron DESY , Notkestrasse 85 , D-22607 Hamburg , Germany
- Institut für Physik , Johannes Gutenberg-Universität , Staudingerweg 7 , D-55099 Mainz , Germany
| | - Andrea Locatelli
- Elettra Sincrotrone Trieste S.C.p.A. , S.S. 14 km 163.5 in AREA Science Park, I-34149 Basovizza , Trieste , Italy
| | - Tevfik Onur Menteş
- Elettra Sincrotrone Trieste S.C.p.A. , S.S. 14 km 163.5 in AREA Science Park, I-34149 Basovizza , Trieste , Italy
| | - Alessandro Sala
- Elettra Sincrotrone Trieste S.C.p.A. , S.S. 14 km 163.5 in AREA Science Park, I-34149 Basovizza , Trieste , Italy
| | - Dmitrii Potorochin
- Deutsches Elektronen-Synchrotron DESY , Notkestrasse 85 , D-22607 Hamburg , Germany
- National Research University of Information Technologies, Mechanics and Optics , Kronverksky prospekt 49 , 197101 Saint Petersburg , Russian Federation
- Institute of Experimental Physics , TU Bergakademie Freiberg , Leipziger Straße 23 , D-09599 Freiberg , Germany
| | - Dmitry Marchenko
- Helmholtz-Zentrum Berlin für Materialien und Energie , Albert-Einstein-Straße 15 , D-12489 Berlin , Germany
| | - Barry Murphy
- CRANN, School of Physics , Trinity College Dublin , Dublin 2 , Ireland
| | - Brian Walls
- CRANN, School of Physics , Trinity College Dublin , Dublin 2 , Ireland
| | | | - Igor V Shvets
- CRANN, School of Physics , Trinity College Dublin , Dublin 2 , Ireland
| |
Collapse
|