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Xi Z, Liu Z, Yan S, Liu M, Zhang JH, Guo X, Li L, Ma W, Li S, Yang L, Jiang M, Tang W. Continuous Tunable Energy Band Tailoring Boosts Extending the Sensing of the Waveband Based on (In xGa 1-x) 2O 3 Solar-Blind Photodetectors. J Phys Chem Lett 2024:4906-4912. [PMID: 38683690 DOI: 10.1021/acs.jpclett.4c00812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Rising wide bandgap semiconductor gallium oxide (Ga2O3) displays huge potential in performing solar-blind photodetection, with constraint in narrow detection wavebands in nature, whereas bandgap modulation through the introduction of exotic atoms into Ga2O3 has an essential effect on the tunable performance of photodetectors and the detection waveband. Here, a novel method for the preparation of (InxGa1-x)2O3 alloy films is proposed, and the continuous tuning of the bandgap in the range of 3.70-4.99 eV is achieved by varying the In-doping content. Alloy-based metal-semiconductor-metal photodetectors were fabricated, achieving a peak responsivity between 254 and 295 nm, superior performance compared to Ga2O3 photodetectors, with a photo-to-dark current ratio as high as 106, and a better optical image-sensing capability. This study offers new insight for high-performance detection of full solar-blind waveband ultraviolet light.
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Affiliation(s)
- Zhaoying Xi
- Innovation Center for Gallium Oxide Semiconductor (IC-GAO), College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210023, People's Republic of China
| | - Zeng Liu
- School of Electronic Information Engineering, Inner Mongolia University, Hohhot, Inner Mongolia 010021, People's Republic of China
| | - Sihan Yan
- Innovation Center for Gallium Oxide Semiconductor (IC-GAO), College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210023, People's Republic of China
| | - Maosheng Liu
- College of Science, MIIT Key Laboratory of Aerospace Information Materials and Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 211106, People's Republic of China
| | - Jia-Han Zhang
- School of Electronic Information Engineering, Inner Mongolia University, Hohhot, Inner Mongolia 010021, People's Republic of China
| | - Xin Guo
- School of Information and Communication Engineering, North University of China, Taiyuan, Shanxi 030051, People's Republic of China
| | - Lei Li
- Innovation Center for Gallium Oxide Semiconductor (IC-GAO), College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210023, People's Republic of China
| | - Wanyu Ma
- Innovation Center for Gallium Oxide Semiconductor (IC-GAO), College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210023, People's Republic of China
| | - Shan Li
- Innovation Center for Gallium Oxide Semiconductor (IC-GAO), College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210023, People's Republic of China
| | - Lili Yang
- Innovation Center for Gallium Oxide Semiconductor (IC-GAO), College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210023, People's Republic of China
| | - Mingming Jiang
- College of Science, MIIT Key Laboratory of Aerospace Information Materials and Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 211106, People's Republic of China
| | - Weihua Tang
- Innovation Center for Gallium Oxide Semiconductor (IC-GAO), College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210023, People's Republic of China
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2
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Charnas A, Zhang Z, Lin Z, Zheng D, Zhang J, Si M, Ye PD. Review-Extremely Thin Amorphous Indium Oxide Transistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2304044. [PMID: 37957006 DOI: 10.1002/adma.202304044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 09/30/2023] [Indexed: 11/21/2023]
Abstract
Amorphous oxide semiconductor transistors have been a mature technology in display panels for upward of a decade, and have recently been considered as promising back-end-of-line compatible channel materials for monolithic 3D applications. However, achieving high-mobility amorphous semiconductor materials with comparable performance to traditional crystalline semiconductors has been a long-standing problem. Recently it has been found that greatly reducing the thickness of indium oxide, enabled by an atomic layer deposition (ALD) process, can tune its material properties to achieve high mobility, high drive current, high on/off ratio, and enhancement-mode operation at the same time, beyond the capabilities of conventional oxide semiconductor materials. In this work, the history leading to the re-emergence of indium oxide, its fundamental material properties, growth techniques with a focus on ALD, state-of-the-art indium oxide device research, and the bias stability of the devices are reviewed.
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Affiliation(s)
- Adam Charnas
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
| | - Zhuocheng Zhang
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
| | - Zehao Lin
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
| | - Dongqi Zheng
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
| | - Jie Zhang
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
| | - Mengwei Si
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
- Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Peide D Ye
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
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3
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Bangolla HK, Yusuf Fakhri M, Lin CH, Cheng CM, Lu YH, Fu TY, Selvarasu P, Ulaganathan RK, Sankar R, Chen RS. Electrical and optoelectronic anisotropy and surface electron accumulation in ReS 2 nanostructures. NANOSCALE 2023. [PMID: 38047470 DOI: 10.1039/d3nr04830f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Two interesting electronic transport properties including in-plane anisotropy and nonhomogeneous carrier distribution were observed in ReS2 nanoflakes. The electrical conductivity defined by the current parallel to the b-axis (‖b) is 32 times higher than that perpendicular to the b-axis (⊥b). Similar anisotropy was also observed in optoelectronic properties in which the ratio of responsivity ‖b to ⊥b reaches 20. In addition, conductivity and thermal activation energy with substantial thickness dependence were observed, which indicates a surface-dominant 2D transport in ReS2 nanoflakes. The presence of surface electron accumulation (SEA) in ReS2 has been confirmed by angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy. The electron concentration (∼1019 cm-3) at the surface is over three orders of magnitude higher than that of the bulks. Sulfur vacancies which are sensitive to air molecules are suggested to be the major factor resulting in SEA and high conductivity in ReS2 nanostructures.
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Affiliation(s)
- Hemanth Kumar Bangolla
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
| | - Muhammad Yusuf Fakhri
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
| | - Ching-Hsuan Lin
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
| | - Cheng-Maw Cheng
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, National Science and Technology Council, Taipei 10601, Taiwan
| | - Yi-Hung Lu
- Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Tsu-Yi Fu
- Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Pushpa Selvarasu
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
| | | | - Raman Sankar
- Institute of Physics, Academia Sinica, Taipei 115201, Taiwan
| | - Ruei-San Chen
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
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4
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Wang R, Schultz T, Papadogianni A, Longhi E, Gatsios C, Zu F, Zhai T, Barlow S, Marder SR, Bierwagen O, Amsalem P, Koch N. Tuning the Surface Electron Accumulation Layer of In 2 O 3 by Adsorption of Molecular Electron Donors and Acceptors. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2300730. [PMID: 37078833 DOI: 10.1002/smll.202300730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/23/2023] [Indexed: 05/03/2023]
Abstract
In2 O3 , an n-type semiconducting transparent transition metal oxide, possesses a surface electron accumulation layer (SEAL) resulting from downward surface band bending due to the presence of ubiquitous oxygen vacancies. Upon annealing In2 O3 in ultrahigh vacuum or in the presence of oxygen, the SEAL can be enhanced or depleted, as governed by the resulting density of oxygen vacancies at the surface. In this work, an alternative route to tune the SEAL by adsorption of strong molecular electron donors (specifically here ruthenium pentamethylcyclopentadienyl mesitylene dimer, [RuCp*mes]2 ) and acceptors (here 2,2'-(1,3,4,5,7,8-hexafluoro-2,6-naphthalene-diylidene)bis-propanedinitrile, F6 TCNNQ) is demonstrated. Starting from an electron-depleted In2 O3 surface after annealing in oxygen, the deposition of [RuCp*mes]2 restores the accumulation layer as a result of electron transfer from the donor molecules to In2 O3 , as evidenced by the observation of (partially) filled conduction sub-bands near the Fermi level via angle-resolved photoemission spectroscopy, indicating the formation of a 2D electron gas due to the SEAL. In contrast, when F6 TCNNQ is deposited on a surface annealed without oxygen, the electron accumulation layer vanishes and an upward band bending is generated at the In2 O3 surface due to electron depletion by the acceptor molecules. Hence, further opportunities to expand the application of In2 O3 in electronic devices are revealed.
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Affiliation(s)
- Rongbin Wang
- Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, 12489, Berlin, Germany
| | - Thorsten Schultz
- Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, 12489, Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489, Berlin, Germany
| | - Alexandra Papadogianni
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Elena Longhi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Christos Gatsios
- Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, 12489, Berlin, Germany
| | - Fengshuo Zu
- Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, 12489, Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489, Berlin, Germany
| | - Tianshu Zhai
- Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, 12489, Berlin, Germany
| | - Stephen Barlow
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Seth R Marder
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
- Department of Chemical and Biological Engineering and Department of Chemistry, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Oliver Bierwagen
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Patrick Amsalem
- Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, 12489, Berlin, Germany
| | - Norbert Koch
- Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, 12489, Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489, Berlin, Germany
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5
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Shi J, Zhang J, Yang L, Qu M, Qi DC, Zhang KHL. Wide Bandgap Oxide Semiconductors: from Materials Physics to Optoelectronic Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006230. [PMID: 33797084 DOI: 10.1002/adma.202006230] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 12/30/2020] [Indexed: 06/12/2023]
Abstract
Wide bandgap oxide semiconductors constitute a unique class of materials that combine properties of electrical conductivity and optical transparency. They are being widely used as key materials in optoelectronic device applications, including flat-panel displays, solar cells, OLED, and emerging flexible and transparent electronics. In this article, an up-to-date review on both the fundamental understanding of materials physics of oxide semiconductors, and recent research progress on design of new materials and high-performing thin film transistor (TFT) devices in the context of fundamental understanding is presented. In particular, an in depth overview is first provided on current understanding of the electronic structures, defect and doping chemistry, optical and transport properties of oxide semiconductors, which provide essential guiding principles for new material design and device optimization. With these principles, recent advances in design of p-type oxide semiconductors, new approaches for achieving cost-effective transparent (flexible) electrodes, and the creation of high mobility 2D electron gas (2DEG) at oxide surfaces and interfaces with a wealth of fascinating physical properties of great potential for novel device design are then reviewed. Finally, recent progress and perspective of oxide TFT based on new oxide semiconductors, 2DEG, and low-temperature solution processed oxide semiconductor for flexible electronics will be reviewed.
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Affiliation(s)
- Jueli Shi
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Jiaye Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Lu Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Mei Qu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Dong-Chen Qi
- Centre for Materials Science, School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland, 4001, Australia
| | - Kelvin H L Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
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6
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Blackman C. Do We Need "Ionosorbed" Oxygen Species? (Or, "A Surface Conductivity Model of Gas Sensitivity in Metal Oxides Based on Variable Surface Oxygen Vacancy Concentration"). ACS Sens 2021; 6:3509-3516. [PMID: 34570973 DOI: 10.1021/acssensors.1c01727] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The author provides an opinion on direct experimental evidence available to support the "ionosorption theory" often employed to interpret "electrophysical" measurements made during a gas sensing experiment. This article then aims to provide an alternative framework of a "surface conductivity" model based on recent advances in theoretical and experimental investigations in solid state physics, and to use this framework as a guide toward design rules for future improvement of gas sensor performance.
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Affiliation(s)
- Christopher Blackman
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
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7
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Hartley P, Egdell RG, Zhang KHL, Hohmann MV, Piper LFJ, Morgan DJ, Scanlon DO, Williamson BAD, Regoutz A. Experimental and Theoretical Study of the Electronic Structures of Lanthanide Indium Perovskites LnInO 3. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:6387-6400. [PMID: 33868543 PMCID: PMC8042864 DOI: 10.1021/acs.jpcc.0c11592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Ternary lanthanide indium oxides LnInO3 (Ln = La, Pr, Nd, Sm) were synthesized by high-temperature solid-state reaction and characterized by X-ray powder diffraction. Rietveld refinement of the powder patterns showed the LnInO3 materials to be orthorhombic perovskites belonging to the space group Pnma, based on almost-regular InO6 octahedra and highly distorted LnO12 polyhedra. Experimental structural data were compared with results from density functional theory (DFT) calculations employing a hybrid Hamiltonian. Valence region X-ray photoelectron and K-shell X-ray emission and absorption spectra of the LnInO3 compounds were simulated with the aid of the DFT calculations. Photoionization of lanthanide 4f orbitals gives rise to a complex final-state multiplet structure in the valence region for the 4f n compounds PrInO3, NdInO3, and SmInO3, and the overall photoemission spectral profiles were shown to be a superposition of final-state 4f n-1 terms onto the cross-section weighted partial densities of states from the other orbitals. The occupied 4f states are stabilized in moving across the series Pr-Nd-Sm. Band gaps were measured using diffuse reflectance spectroscopy. These results demonstrated that the band gap of LaInO3 is 4.32 eV, in agreement with DFT calculations. This is significantly larger than a band gap of 2.2 eV first proposed in 1967 and based on the idea that In 4d states lie above the top of the O 2p valence band. However, both DFT and X-ray spectroscopy show that In 4d is a shallow core level located well below the bottom of the valence band. Band gaps greater than 4 eV were observed for NdInO3 and SmInO3, but a lower gap of 3.6 eV for PrInO3 was shown to arise from the occupied Pr 4f states lying above the main O 2p valence band.
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Affiliation(s)
- P. Hartley
- Department
of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K.
| | - R. G. Egdell
- Department
of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K.
| | - K. H. L. Zhang
- Department
of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K.
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, College of
Chemistry and Chemical Engineering, Xiamen
University, Xiamen 361005, People’s Republic
of China
| | - M. V. Hohmann
- Department
of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K.
- Institute
of Materials Science, Surface Science Division, Technische Universität Darmstadt, Darmstadt 64287, Germany
| | - L. F. J. Piper
- WMG, The University of Warwick, Coventry CV4 7AL, U.K.
- Department
of Applied Physics & Astronomy, Binghamton
University, State University of New York, Binghamton, New York 13902, United States
| | - D. J. Morgan
- Cardiff Catalysis
Institute, School of Chemistry, Cardiff
University, Park Place, Cardiff CF10
3AT, U.K.
| | - D. O. Scanlon
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
- Diamond
Light Source Ltd., Diamond
House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11
0DE, U.K.
| | - B. A. D. Williamson
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), Trondheim 7491, Norway
| | - A. Regoutz
- Department
of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K.
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
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8
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Gong Y, Yang Z, Lari L, Azaceta I, Lazarov VK, Zhang J, Xu X, Cheng Q, Zhang KHL. Optimizing the Electronic Structure of In 2O 3 through Mg Doping for NiO/In 2O 3 p-n Heterojunction Diodes. ACS APPLIED MATERIALS & INTERFACES 2020; 12:53446-53453. [PMID: 33191725 DOI: 10.1021/acsami.0c14348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In2O3 is a wide bandgap oxide semiconductor, which has the potential to be used as an active material for transparent flexible electronics and UV photodetectors. However, the high concentration of unintentional background electrons existing in In2O3 makes it hard to be modulated by the electric field or form p-n heterojunctions with a sufficient band-bending width at the interface. In this work, we report the reduction of the background electrons in In2O3 by Mg doping (Mg-In2O3) and thereby improve the device performance of p-n diodes based on the NiO/Mg-In2O3 heterojunction. In particular, Mg doping compensates the free electrons in In2O3 and reduces the electron concentration from 1.7 × 1019 cm-3 without doping to 1.8 × 1017 cm-3 with 5% Mg doping. Transparent p-n heterojunction diodes were fabricated based on p-type NiO and n-type Mg-In2O3. The device performance was considerably enhanced by Mg doping with a high rectification ratio of 3 × 104 and a remarkable high breakdown voltage of >20 V. High-resolution X-ray photoelectron spectroscopy was used to investigate the interfacial electronic structure between NiO and Mg-In2O3, revealing a type II band alignment with a valence band offset of 1.35 eV and a conduction band offset of 2.15 eV. A large built-in potential of 0.98 eV was found for the undoped In2O3 but decreased to 0.51 eV for 5% Mg doping of In2O3. The NiO/Mg-In2O3 diodes with an improved rectification ratio and wider depletion region provide the possibility of achieving photodetectors with rapid photoresponse.
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Affiliation(s)
| | | | - Leonardo Lari
- Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Irene Azaceta
- Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Vlado K Lazarov
- Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
| | | | | | - Qijin Cheng
- Shenzhen Research Institute of Xiamen University, Shenzhen 518000, P. R. China
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9
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Nagata T, Hoga T, Yamashita A, Asahi T, Yagyu S, Chikyow T. Valence Band Modification of a (Ga xIn 1-x) 2O 3 Solid Solution System Fabricated by Combinatorial Synthesis. ACS COMBINATORIAL SCIENCE 2020; 22:433-439. [PMID: 32659073 DOI: 10.1021/acscombsci.0c00033] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The correlation between the crystal structure and valence band structure of a (GaxIn1-x)2O3 solid solution system was investigated by using combinatorial synthesis. At a low Ga content of (GaxIn1-x)2O3 with a single-phase cubic In2O3 crystal structure, a surface electron accumulation layer (SEAL), which is an important electrical phenomenon in In2O3, was confirmed. When the Ga content increased to approximately x = 0.4, mixed crystal structures of Ga2O3 and In2O3 were produced. Above x = 0.5, the dominant valence band structure was attributed to Ga2O3, the SEAL disappeared, and the sheet resistance increased greatly by 5 orders of magnitude or more. The in-gap state and valence band structure of the (GaxIn1-x)2O3 solid solution system were strongly affected by Ga2O3; however, the valence band maximum position shifted to a higher binding energy.
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Affiliation(s)
- Takahiro Nagata
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takeshi Hoga
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
- Department of Creative Engineering, National Institute of Technology, Tsuruoka College, 104 Sawada, Inooka, Tsuruoka, Yamagata 997-8511, Japan
| | - Akihiro Yamashita
- Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169−8555, Japan
- Materials Data & Integrated System (MaDIS), NIMS, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Toru Asahi
- Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169−8555, Japan
| | - Shinjiro Yagyu
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Toyohiro Chikyow
- Materials Data & Integrated System (MaDIS), NIMS, 1-1 Namiki, Tsukuba 305-0044, Japan
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10
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Jovic V, Moser S, Papadogianni A, Koch RJ, Rossi A, Jozwiak C, Bostwick A, Rotenberg E, Kennedy JV, Bierwagen O, Smith KE. The Itinerant 2D Electron Gas of the Indium Oxide (111) Surface: Implications for Carbon- and Energy-Conversion Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1903321. [PMID: 31489781 DOI: 10.1002/smll.201903321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Transparent conducting oxides (TCO) have integral and emerging roles in photovoltaic, thermoelectric energy conversion, and more recently, photocatalytic systems. The functional properties of TCOs, and thus their role in these applications, are often mediated by the bulk electronic band structure but are also strongly influenced by the electronic structure of the native surface 2D electron gas (2DEG), particularly under operating conditions. This study investigates the 2DEG, and its response to changes in chemistry, at the (111) surface of the model TCO In2 O3 , through angle resolved and core level X-ray photoemission spectroscopy. It is found that the itinerant charge carriers of the 2DEG reside in two quantum well subbands penetrating up to 65 Å below the surface. The charge carrier concentration of this 2DEG, and thus the high surface n-type conductivity, emerges from donor-type oxygen vacancies of surface character and proves to be remarkably robust against surface absorbents and contamination. The optical transparency, however, may rely on the presence of ubiquitous surface adsorbed oxygen groups and hydrogen defect states that passivate localized oxygen vacancy states in the bandgap of In2 O3 .
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Affiliation(s)
- Vedran Jovic
- National Isotope Center, GNS Science, MacDiarmid Institute for Advanced Materials and Nanotechnology, Lower Hutt, Wellington, 5010, New Zealand
- School of Chemical Sciences, The University of Auckland, Auckland, 1010, New Zealand
| | - Simon Moser
- Physikalisches Institut, Universität Würzburg, Würzburg, D-97074, Germany
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Alexandra Papadogianni
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, Berlin, 10117, Germany
| | - Roland J Koch
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Antonio Rossi
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Davis, CA, 95616, USA
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Aaron Bostwick
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Eli Rotenberg
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - John V Kennedy
- National Isotope Center, GNS Science, MacDiarmid Institute for Advanced Materials and Nanotechnology, Lower Hutt, Wellington, 5010, New Zealand
| | - Oliver Bierwagen
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, Berlin, 10117, Germany
| | - Kevin E Smith
- Department of Physics, Boston University, Boston, MA, 02215, USA
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11
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Two-dimensional Electron Gas at Thiol/ZnO Interface. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2020. [DOI: 10.1380/ejssnt.2020.41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Daelman N, Hegner FS, Rellán-Piñeiro M, Capdevila-Cortada M, García-Muelas R, López N. Quasi-degenerate states and their dynamics in oxygen deficient reducible metal oxides. J Chem Phys 2020; 152:050901. [PMID: 32035446 DOI: 10.1063/1.5138484] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The physical and chemical properties of oxides are defined by the presence of oxygen vacancies. Experimentally, non-defective structures are almost impossible to achieve due to synthetic constraints. Therefore, it is crucial to account for vacancies when evaluating the characteristics of these materials. The electronic structure of oxygen-depleted oxides deeply differs from that of the native forms, in particular, of reducible metal oxides, where excess electrons can localize in various distinct positions. In this perspective, we present recent developments from our group describing the complexity of these defective materials that highlight the need for an accurate description of (i) intrinsic vacancies in polar terminations, (ii) multiple geometries and complex electronic structures with several states attainable at typical working conditions, and (iii) the associated dynamics for both vacancy diffusion and the coexistence of more than one electronic structure. All these aspects widen our current understanding of defects in oxides and need to be adequately introduced in emerging high-throughput screening methodologies.
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Affiliation(s)
- Nathan Daelman
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, BIST, Av. Països Catalans 16, 43007 Tarragona, Spain
| | - Franziska Simone Hegner
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, BIST, Av. Països Catalans 16, 43007 Tarragona, Spain
| | - Marcos Rellán-Piñeiro
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, BIST, Av. Països Catalans 16, 43007 Tarragona, Spain
| | - Marçal Capdevila-Cortada
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, BIST, Av. Països Catalans 16, 43007 Tarragona, Spain
| | - Rodrigo García-Muelas
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, BIST, Av. Països Catalans 16, 43007 Tarragona, Spain
| | - Núria López
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, BIST, Av. Països Catalans 16, 43007 Tarragona, Spain
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13
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Han F, Zhao W, Bi R, Tian F, Li Y, Zheng C, Wang Y. Influence Mechanism of Cu Layer Thickness on Photoelectric Properties of IWO/Cu/IWO Films. MATERIALS 2019; 13:ma13010113. [PMID: 31881786 PMCID: PMC6982096 DOI: 10.3390/ma13010113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 11/16/2022]
Abstract
Transparent conductive IWO/Cu/IWO (W-doped In2O3) films were deposited on quartz substrates by magnetron sputtering of IWO and Cu in the Ar atmosphere. The X-ray diffraction (XRD) patterns identified the cubic iron-manganese ore crystal structure of the IWO layers. The influence of the thickness of the intermediate ultra-thin Cu layers on the optical and electrical properties of the multilayer films was analyzed. As the Cu layer thickness increases from 4 to 10 nm, the multilayer resistivity gradually decreases to 4.5 × 10-4 Ω·cm, and the optical transmittance in the mid-infrared range increases first and then decreases with a maximum of 72%, which serves as an excellent candidate for the mid-infrared transparent electrode.
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14
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Wang H, Jia J, Wang L, Butler K, Song R, Casillas G, He L, Kherani NP, Perovic DD, Jing L, Walsh A, Dittmeyer R, Ozin GA. Heterostructure Engineering of a Reverse Water Gas Shift Photocatalyst. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1902170. [PMID: 31763158 PMCID: PMC6864495 DOI: 10.1002/advs.201902170] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/16/2019] [Indexed: 05/15/2023]
Abstract
To achieve substantial reductions in CO2 emissions, catalysts for the photoreduction of CO2 into value-added chemicals and fuels will most likely be at the heart of key renewable-energy technologies. Despite tremendous efforts, developing highly active and selective CO2 reduction photocatalysts remains a great challenge. Herein, a metal oxide heterostructure engineering strategy that enables the gas-phase, photocatalytic, heterogeneous hydrogenation of CO2 to CO with high performance metrics (i.e., the conversion rate of CO2 to CO reached as high as 1400 µmol g cat-1 h-1) is reported. The catalyst is comprised of indium oxide nanocrystals, In2O3- x (OH) y , nucleated and grown on the surface of niobium pentoxide (Nb2O5) nanorods. The heterostructure between In2O3- x (OH) y nanocrystals and the Nb2O5 nanorod support increases the concentration of oxygen vacancies and prolongs excited state (electron and hole) lifetimes. Together, these effects result in a dramatically improved photocatalytic performance compared to the isolated In2O3- x (OH) y material. The defect optimized heterostructure exhibits a 44-fold higher conversion rate than pristine In2O3- x (OH) y . It also exhibits selective conversion of CO2 to CO as well as long-term operational stability.
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Affiliation(s)
- Hong Wang
- Key Laboratory of Functional Polymer Materials of the Ministry of EducationInstitute of Polymer ChemistryCollege of ChemistryNankai UniversityTianjin300071P. R. China
| | - Jia Jia
- Materials Chemistry and Nanochemistry Research GroupSolar Fuels ClusterDepartments of ChemistryUniversity of Toronto80 St. George StreetTorontoONM5S3H6Canada
- Department of Materials Science and EngineeringUniversity of Toronto184 College StreetTorontoONM5S3E4Canada
| | - Lu Wang
- Materials Chemistry and Nanochemistry Research GroupSolar Fuels ClusterDepartments of ChemistryUniversity of Toronto80 St. George StreetTorontoONM5S3H6Canada
- Institute of Functional Nano & Soft Materials (FUNSOM)Jiangsu Key Laboratory for Carbon‐Based Functional Materials & DevicesSoochow University199 Ren'ai RoadSuzhouJiangsuP. R. China
| | - Keith Butler
- SciML, Scientific Computing Department, Rutherford Appleton LaboratoryDidcotOX110QXUK
| | - Rui Song
- Materials Chemistry and Nanochemistry Research GroupSolar Fuels ClusterDepartments of ChemistryUniversity of Toronto80 St. George StreetTorontoONM5S3H6Canada
| | - Gilberto Casillas
- UOW Electron Microscopy Centre, University of WollongongWollongongNew South Wales2500Australia
| | - Le He
- Institute of Functional Nano & Soft Materials (FUNSOM)Jiangsu Key Laboratory for Carbon‐Based Functional Materials & DevicesSoochow University199 Ren'ai RoadSuzhouJiangsuP. R. China
| | - Nazir P. Kherani
- Department of Materials Science and EngineeringUniversity of Toronto184 College StreetTorontoONM5S3E4Canada
| | - Doug D. Perovic
- Department of Materials Science and EngineeringUniversity of Toronto184 College StreetTorontoONM5S3E4Canada
| | - Liqiang Jing
- Key Laboratory of Functional Inorganic Material ChemistryMinistry of Education School of Chemistry and Materials ScienceInternational Joint Research Center for Catalytic TechnologyHeilongjiang UniversityHarbin150080P. R. China
| | - Aron Walsh
- Department of Materials, Imperial College LondonExhibition RoadLondonSW7 2AZUK
- Department of Materials Science and Engineering, Yonsei UniversitySeoul03722Korea
| | - Roland Dittmeyer
- Institute for Micro Process Engineering, Karlsruhe Institute of TechnologyHermann‐von‐Helmholtz‐Platz 176344Eggenstein‐LeopoldshafenGermany
| | - Geoffrey A. Ozin
- Materials Chemistry and Nanochemistry Research GroupSolar Fuels ClusterDepartments of ChemistryUniversity of Toronto80 St. George StreetTorontoONM5S3H6Canada
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15
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Schuurman JC, McNeill AR, Martinez-Gazoni RF, Scott JI, Reeves RJ, Allen MW, Downard AJ. The effect of covalently bonded aryl layers on the band bending and electron density of SnO2 surfaces probed by synchrotron X-ray photoelectron spectroscopy. Phys Chem Chem Phys 2019; 21:17913-17922. [DOI: 10.1039/c9cp03040a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A downward to upward surface band bending change can be induced by grafted 4-(trifluoromethyl)phenyl groups on SnO2.
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Affiliation(s)
- Joel C. Schuurman
- School of Physical and Chemical Sciences
- University of Canterbury
- Christchurch 8140
- New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology
| | - Alexandra R. McNeill
- School of Physical and Chemical Sciences
- University of Canterbury
- Christchurch 8140
- New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology
| | - Rodrigo F. Martinez-Gazoni
- School of Physical and Chemical Sciences
- University of Canterbury
- Christchurch 8140
- New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology
| | - Jonty I. Scott
- School of Physical and Chemical Sciences
- University of Canterbury
- Christchurch 8140
- New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology
| | - Roger J. Reeves
- School of Physical and Chemical Sciences
- University of Canterbury
- Christchurch 8140
- New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology
| | - Martin W. Allen
- MacDiarmid Institute for Advanced Materials and Nanotechnology
- Wellington 6012
- New Zealand
- Department of Electrical and Computer Engineering
- University of Canterbury
| | - Alison J. Downard
- School of Physical and Chemical Sciences
- University of Canterbury
- Christchurch 8140
- New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology
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16
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Shin WH, Roh JW, Ryu B, Chang HJ, Kim HS, Lee S, Seo WS, Ahn K. Enhancing Thermoelectric Performances of Bismuth Antimony Telluride via Synergistic Combination of Multiscale Structuring and Band Alignment by FeTe 2 Incorporation. ACS APPLIED MATERIALS & INTERFACES 2018; 10:3689-3698. [PMID: 29303242 DOI: 10.1021/acsami.7b18451] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
It has been a difficulty to form well-distributed nano- and mesosized inclusions in a Bi2Te3-based matrix and thereby realizing no degradation of carrier mobility at interfaces between matrix and inclusions for high thermoelectric performances. Herein, we successfully synthesize multistructured thermoelectric Bi0.4Sb1.6Te3 materials with Fe-rich nanoprecipitates and sub-micron FeTe2 inclusions by a conventional solid-state reaction followed by melt-spinning and spark plasma sintering that could be a facile preparation method for scale-up production. This study presents a bismuth antimony telluride based thermoelectric material with a multiscale structure whose lattice thermal conductivity is drastically reduced with minimal degradation on its carrier mobility. This is possible because a carefully chosen FeTe2 incorporated in the matrix allows its interfacial valence band with the matrix to be aligned, leading to a significantly improved p-type thermoelectric power factor. Consequently, an impressively high thermoelectric figure of merit ZT of 1.52 is achieved at 396 K for p-type Bi0.4Sb1.6Te3-8 mol % FeTe2, which is a 43% enhancement in ZT compared to the pristine Bi0.4Sb1.6Te3. This work demonstrates not only the effectiveness of multiscale structuring for lowering lattice thermal conductivities, but also the importance of interfacial band alignment between matrix and inclusions for maintaining high carrier mobilities when designing high-performance thermoelectric materials.
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Affiliation(s)
- Weon Ho Shin
- Energy Materials Center, Energy & Environment Division, Korea Institute of Ceramic Engineering & Technology , Jinju 52851, Republic of Korea
| | - Jong Wook Roh
- Materials R&D Center, Samsung Advanced Institute of Technology, Samsung Electronics , Suwon 16419, Republic of Korea
| | - Byungki Ryu
- Thermoelectric Conversion Research Center, Creative and Fundamental Research Division, Korea Electrotechnology Research Institute , Changwon 51543, Republic of Korea
| | - Hye Jung Chang
- Advanced Analysis Center, Korea Institute of Science and Technology , Seoul 02792, Republic of Korea
| | - Hyun Sik Kim
- Materials R&D Center, Samsung Advanced Institute of Technology, Samsung Electronics , Suwon 16419, Republic of Korea
| | - Soonil Lee
- Energy Materials Center, Energy & Environment Division, Korea Institute of Ceramic Engineering & Technology , Jinju 52851, Republic of Korea
| | - Won Seon Seo
- Energy Materials Center, Energy & Environment Division, Korea Institute of Ceramic Engineering & Technology , Jinju 52851, Republic of Korea
| | - Kyunghan Ahn
- Department of Chemistry, Chung-Ang University , Seoul 06974, Republic of Korea
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17
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Albani D, Capdevila-Cortada M, Vilé G, Mitchell S, Martin O, López N, Pérez-Ramírez J. Semihydrogenation of Acetylene on Indium Oxide: Proposed Single-Ensemble Catalysis. Angew Chem Int Ed Engl 2017; 56:10755-10760. [DOI: 10.1002/anie.201704999] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 06/24/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Davide Albani
- ETH Zurich; Department of Chemistry and Applied Biosciences; Institute for Chemical and Bioengineering; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - Marçal Capdevila-Cortada
- Institute of Chemical Research of Catalonia (ICIQ) and; The Barcelona Institute of Science and Technology; Av. Països Catalans 16 43007 Tarragona Spain
| | - Gianvito Vilé
- ETH Zurich; Department of Chemistry and Applied Biosciences; Institute for Chemical and Bioengineering; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - Sharon Mitchell
- ETH Zurich; Department of Chemistry and Applied Biosciences; Institute for Chemical and Bioengineering; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - Oliver Martin
- ETH Zurich; Department of Chemistry and Applied Biosciences; Institute for Chemical and Bioengineering; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - Núria López
- Institute of Chemical Research of Catalonia (ICIQ) and; The Barcelona Institute of Science and Technology; Av. Països Catalans 16 43007 Tarragona Spain
| | - Javier Pérez-Ramírez
- ETH Zurich; Department of Chemistry and Applied Biosciences; Institute for Chemical and Bioengineering; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
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18
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Albani D, Capdevila-Cortada M, Vilé G, Mitchell S, Martin O, López N, Pérez-Ramírez J. Semihydrogenation of Acetylene on Indium Oxide: Proposed Single-Ensemble Catalysis. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704999] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Davide Albani
- ETH Zurich; Department of Chemistry and Applied Biosciences; Institute for Chemical and Bioengineering; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - Marçal Capdevila-Cortada
- Institute of Chemical Research of Catalonia (ICIQ) and; The Barcelona Institute of Science and Technology; Av. Països Catalans 16 43007 Tarragona Spain
| | - Gianvito Vilé
- ETH Zurich; Department of Chemistry and Applied Biosciences; Institute for Chemical and Bioengineering; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - Sharon Mitchell
- ETH Zurich; Department of Chemistry and Applied Biosciences; Institute for Chemical and Bioengineering; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - Oliver Martin
- ETH Zurich; Department of Chemistry and Applied Biosciences; Institute for Chemical and Bioengineering; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - Núria López
- Institute of Chemical Research of Catalonia (ICIQ) and; The Barcelona Institute of Science and Technology; Av. Països Catalans 16 43007 Tarragona Spain
| | - Javier Pérez-Ramírez
- ETH Zurich; Department of Chemistry and Applied Biosciences; Institute for Chemical and Bioengineering; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
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19
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Lee SY, Kim J, Park A, Park J, Seo H. Creation of a Short-Range Ordered Two-Dimensional Electron Gas Channel in Al 2O 3/In 2O 3 Interfaces. ACS NANO 2017; 11:6040-6047. [PMID: 28521101 DOI: 10.1021/acsnano.7b01964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The tuning of electrical properties in oxides via surface and interfacial two-dimensional electron gas (2DEG) channels is of great interest, as they reveal the extraordinary transition from insulating or semiconducting characteristics to metallic conduction or superconductivity enabled by the ballistic transport of spatially confined electrons. However, realizing the practical aspects of this exotic phenomenon toward short-range ordered and air-stable 2DEG channels remains a great challenge. At the heterointerface formed after deposition of an Al2O3 layer on a nanocrystalline In2O3 layer, a dramatic improvement in carrier conduction equivalent to metallic conduction is obtained. A conductivity increase by a factor of 1013 times that in raw In2O3, a sheet resistance of 850 Ω/cm2, and a room temperature Hall mobility of 20.5 cm2 V-1 s-1 are obtained, which are impossible to achieve by tuning each layer individually. The physicochemical origin of metallic conduction is mainly ascribed to the 2D interfacially confined O-vacancies and semimetallic nanocrystalline InOx (x < 2) phases by the clustered self-doping effect caused by O-extraction from In2O3 to the Al2O3 phase during ALD. Unlike other submetallic oxides, this 2D channel is air-stable by complete Al2O3 passivation and thereby promises applicability for implementation in devices.
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Affiliation(s)
- Sang Yeon Lee
- Department of Energy Systems Research & Department of Materials Science and Engineering, Ajou University , Suwon 16499, Republic of Korea
| | - Jinseo Kim
- Department of Energy Systems Research & Department of Materials Science and Engineering, Ajou University , Suwon 16499, Republic of Korea
| | - Ayoung Park
- Department of Energy Systems Research & Department of Materials Science and Engineering, Ajou University , Suwon 16499, Republic of Korea
| | - Jucheol Park
- Gyeongbuk Science Technology Promotion Center, Gumi Electronics & Information Technology Research Institute , Gumi 39171, Republic of Korea
| | - Hyungtak Seo
- Department of Energy Systems Research & Department of Materials Science and Engineering, Ajou University , Suwon 16499, Republic of Korea
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20
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Carrier dynamics and the role of surface defects: Designing a photocatalyst for gas-phase CO2 reduction. Proc Natl Acad Sci U S A 2016; 113:E8011-E8020. [PMID: 27911785 DOI: 10.1073/pnas.1609374113] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In2O3-x(OH)y nanoparticles have been shown to function as an effective gas-phase photocatalyst for the reduction of CO2 to CO via the reverse water-gas shift reaction. Their photocatalytic activity is strongly correlated to the number of oxygen vacancy and hydroxide defects present in the system. To better understand how such defects interact with photogenerated electrons and holes in these materials, we have studied the relaxation dynamics of In2O3-x(OH)y nanoparticles with varying concentration of defects using two different excitation energies corresponding to above-band-gap (318-nm) and near-band-gap (405-nm) excitations. Our results demonstrate that defects play a significant role in the excited-state, charge relaxation pathways. Higher defect concentrations result in longer excited-state lifetimes, which are attributed to improved charge separation. This correlates well with the observed trends in the photocatalytic activity. These results are further supported by density-functional theory calculations, which confirm the positions of oxygen vacancy and hydroxide defect states within the optical band gap of indium oxide. This enhanced understanding of the role these defects play in determining the optoelectronic properties and charge carrier dynamics can provide valuable insight toward the rational development of more efficient photocatalytic materials for CO2 reduction.
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21
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Wagner M, Lackner P, Seiler S, Gerhold S, Osiecki J, Schulte K, Boatner LA, Schmid M, Meyer B, Diebold U. Well-Ordered In Adatoms at the In_{2}O_{3}(111) Surface Created by Fe Deposition. PHYSICAL REVIEW LETTERS 2016; 117:206101. [PMID: 27886498 DOI: 10.1103/physrevlett.117.206101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Indexed: 05/27/2023]
Abstract
Metal deposition on oxide surfaces usually results in adatoms, clusters, or islands of the deposited material, where defects in the surface often act as nucleation centers. Here an alternate configuration is reported. After the vapor deposition of Fe on the In_{2}O_{3}(111) surface at room temperature, ordered adatoms are observed with scanning tunneling microscopy. These are identical to the In adatoms that form when the sample is reduced by heating in ultrahigh vacuum. Density functional theory calculations confirm that Fe interchanges with In in the topmost layer, pushing the excess In atoms to the surface where they arrange as a well-ordered adatom array.
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Affiliation(s)
- Margareta Wagner
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Peter Lackner
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Steffen Seiler
- Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, Friedrich-Alexander-University Erlangen-Nürnberg, Nägelsbachstraße 25, 91052 Erlangen, Germany
| | - Stefan Gerhold
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Jacek Osiecki
- MAX IV Laboratory, Lund University, Ole Römers väg 1, 223 63 Lund, Sweden
| | - Karina Schulte
- MAX IV Laboratory, Lund University, Ole Römers väg 1, 223 63 Lund, Sweden
| | - Lynn A Boatner
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Bernd Meyer
- Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, Friedrich-Alexander-University Erlangen-Nürnberg, Nägelsbachstraße 25, 91052 Erlangen, Germany
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
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22
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Zhang KHL, Xi K, Blamire MG, Egdell RG. P-type transparent conducting oxides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:383002. [PMID: 27459942 DOI: 10.1088/0953-8984/28/38/383002] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Transparent conducting oxides constitute a unique class of materials combining properties of electrical conductivity and optical transparency in a single material. They are needed for a wide range of applications including solar cells, flat panel displays, touch screens, light emitting diodes and transparent electronics. Most of the commercially available TCOs are n-type, such as Sn doped In2O3, Al doped ZnO, and F doped SnO2. However, the development of efficient p-type TCOs remains an outstanding challenge. This challenge is thought to be due to the localized nature of the O 2p derived valence band which leads to difficulty in introducing shallow acceptors and large hole effective masses. In 1997 Hosono and co-workers (1997 Nature 389 939) proposed the concept of 'chemical modulation of the valence band' to mitigate this problem using hybridization of O 2p orbitals with close-shell Cu 3d (10) orbitals. This work has sparked tremendous interest in designing p-TCO materials together with deep understanding the underlying materials physics. In this article, we will provide a comprehensive review on traditional and recently emergent p-TCOs, including Cu(+)-based delafossites, layered oxychalcogenides, nd (6) spinel oxides, Cr(3+)-based oxides (3d (3)) and post-transition metal oxides with lone pair state (ns (2)). We will focus our discussions on the basic materials physics of these materials in terms of electronic structures, doping and defect properties for p-type conductivity and optical properties. Device applications based on p-TCOs for transparent p-n junctions will also be briefly discussed.
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Affiliation(s)
- Kelvin H L Zhang
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
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23
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He L, Wood TE, Wu B, Dong Y, Hoch LB, Reyes LM, Wang D, Kübel C, Qian C, Jia J, Liao K, O'Brien PG, Sandhel A, Loh JYY, Szymanski P, Kherani NP, Sum TC, Mims CA, Ozin GA. Spatial Separation of Charge Carriers in In2O3-x(OH)y Nanocrystal Superstructures for Enhanced Gas-Phase Photocatalytic Activity. ACS NANO 2016; 10:5578-86. [PMID: 27159793 DOI: 10.1021/acsnano.6b02346] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The development of strategies for increasing the lifetime of photoexcited charge carriers in nanostructured metal oxide semiconductors is important for enhancing their photocatalytic activity. Intensive efforts have been made in tailoring the properties of the nanostructured photocatalysts through different ways, mainly including band-structure engineering, doping, catalyst-support interaction, and loading cocatalysts. In liquid-phase photocatalytic dye degradation and water splitting, it was recently found that nanocrystal superstructure based semiconductors exhibited improved spatial separation of photoexcited charge carriers and enhanced photocatalytic performance. Nevertheless, it remains unknown whether this strategy is applicable in gas-phase photocatalysis. Using porous indium oxide nanorods in catalyzing the reverse water-gas shift reaction as a model system, we demonstrate here that assembling semiconductor nanocrystals into superstructures can also promote gas-phase photocatalytic processes. Transient absorption studies prove that the improved activity is a result of prolonged photoexcited charge carrier lifetimes due to the charge transfer within the nanocrystal network comprising the nanorods. Our study reveals that the spatial charge separation within the nanocrystal networks could also benefit gas-phase photocatalysis and sheds light on the design principles of efficient nanocrystal superstructure based photocatalysts.
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Affiliation(s)
- Le He
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, People's Republic of China
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Thomas E Wood
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Bo Wu
- Singapore-Berkeley Research Initiative for Sustainable Energy (SinBeRISE) , 1 Create Way, Singapore 138602
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371
| | - Yuchan Dong
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Laura B Hoch
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Laura M Reyes
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Di Wang
- Institute of Nanotechnology and Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology , Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Christian Kübel
- Institute of Nanotechnology and Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology , Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Chenxi Qian
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Jia Jia
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Kristine Liao
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Paul G O'Brien
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Amit Sandhel
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Joel Y Y Loh
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Paul Szymanski
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive NW, Atlanta, Georgia 30332, United States
| | - Nazir P Kherani
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Tze Chien Sum
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371
| | - Charles A Mims
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Geoffrey A Ozin
- Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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Chuai Y, Wang X, Zheng C, Zhang Y, Shen H, Wang Y. Highly infrared-transparent and p-type conductive CuSc 1−xSn xO 2 thin films and a p-CuScO 2:Sn/n-ZnO heterojunction fabricated by the polymer-assisted deposition method. RSC Adv 2016. [DOI: 10.1039/c6ra00919k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We fabricated a series of infrared (IR)-transparent and conductive Sn-doped CuScO2 thin films using a polymer-assisted deposition (PAD) method.
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Affiliation(s)
- Yahui Chuai
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- PR China
| | - Xin Wang
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- PR China
| | - Chuantao Zheng
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- PR China
| | - Yu Zhang
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- PR China
| | - Hongzhi Shen
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- PR China
| | - Yiding Wang
- State Key Laboratory on Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun 130012
- PR China
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26
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Zhang KHL, Du Y, Papadogianni A, Bierwagen O, Sallis S, Piper LFJ, Bowden ME, Shutthanandan V, Sushko PV, Chambers SA. Perovskite Sr-Doped LaCrO3 as a New p-Type Transparent Conducting Oxide. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:5191-5195. [PMID: 26248327 DOI: 10.1002/adma.201501959] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/24/2015] [Indexed: 06/04/2023]
Abstract
Epitaxial La1-x Srx CrO3 deposited on SrTiO3 (001) is shown to be a p-type transparent conducting oxide with competitive figures of merit and a cubic perovskite structure, facilitating integration into oxide electronics. Holes in the Cr 3d t2g bands play a critical role in enhancing p-type conductivity, while transparency to visible light is maintained because low-lying d-d transitions arising from hole doping are dipole forbidden.
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Affiliation(s)
- Kelvin H L Zhang
- Physical Sciences Division, Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Yingge Du
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Alexandra Papadogianni
- Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, DE-10117, Berlin, Germany
| | - Oliver Bierwagen
- Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, DE-10117, Berlin, Germany
| | - Shawn Sallis
- Materials Science and Engineering, Binghamton University, Binghamton, New York, 13902, USA
| | - Louis F J Piper
- Materials Science and Engineering, Binghamton University, Binghamton, New York, 13902, USA
| | - Mark E Bowden
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | | | - Peter V Sushko
- Physical Sciences Division, Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Scott A Chambers
- Physical Sciences Division, Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
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27
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Lin JJ, Li ZQ. Electronic conduction properties of indium tin oxide: single-particle and many-body transport. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:343201. [PMID: 25105780 DOI: 10.1088/0953-8984/26/34/343201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Indium tin oxide (Sn-doped In2O3-δ or ITO) is a very interesting and technologically important transparent conducting oxide. This class of material has been extensively investigated for decades, with research efforts mostly focusing on the application aspects. The fundamental issues of the electronic conduction properties of ITO from room temperature down to liquid-helium temperatures have rarely been addressed thus far. Studies of the electrical-transport properties over a wide range of temperature are essential to unravelling the underlying electronic dynamics and microscopic electronic parameters. In this topical review, we show that one can learn rich physics in ITO material, including the semi-classical Boltzmann transport, the quantum-interference electron transport, as well as the many-body Coulomb electron-electron interaction effects in the presence of disorder and inhomogeneity (granularity). To fully reveal the numerous avenues and unique opportunities that the ITO material has provided for fundamental condensed matter physics research, we demonstrate a variety of charge transport properties in different forms of ITO structures, including homogeneous polycrystalline thin and thick films, homogeneous single-crystalline nanowires and inhomogeneous ultrathin films. In this manner, we not only address new physics phenomena that can arise in ITO but also illustrate the versatility of the stable ITO material forms for potential technological applications. We emphasize that, microscopically, the novel and rich electronic conduction properties of ITO originate from the inherited robust free-electron-like energy bandstructure and low-carrier concentration (as compared with that in typical metals) characteristics of this class of material. Furthermore, a low carrier concentration leads to slow electron-phonon relaxation, which in turn causes the experimentally observed (i) a small residual resistance ratio, (ii) a linear electron diffusion thermoelectric power in a wide temperature range 1-300 K and (iii) a weak electron dephasing rate. We focus our discussion on the metallic-like ITO material.
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Affiliation(s)
- Juhn-Jong Lin
- NCTU-RIKEN Joint Research Laboratory, Institute of Physics and Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
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Regoutz A, Egdell RG, Wermeille D, Cowley RA, Zhang KHL. Strain and tilt during epitaxial growth of highly ordered In2O3 nanorods. NANOSCALE 2013; 5:7445-7451. [PMID: 23832180 DOI: 10.1039/c3nr00728f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Precise control over the morphology of one-dimensional (1D) nanostructures is an essential step in the effort to develop nano-devices with exotic properties. Here we demonstrate the formation of highly aligned In2O3 nanorod arrays on Y-stabilised ZrO2(110) grown by oxygen plasma assisted molecular beam epitaxy. The evolution of morphologies, strain and tilt in the In2O3 nanorods are studied by atomic force microscopy and high resolution synchrotron-based X-ray diffraction. It is shown that the preferential 1D growth is driven by minimization of the total surface and interface energies. The mismatch of ca. 1.7% between the substrate and the epilayer is accommodated by strain along the [110] direction coupled with tilting of the rods along [001] and [001] directions and contraction in the [110] direction. The present highly ordered In2O3 nanorod arrays supported on an insulating substrate are of potential interest for large-scale fabrication of nano-devices.
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Affiliation(s)
- A Regoutz
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
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