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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] [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.
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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
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Tsai MY, Tsai TH, Gandhi AC, Lu HL, Li JX, Chen PL, Chen KW, Chen SZ, Chen CH, Liu CH, Lin YF, Chiu PW. Ultrafast and Broad-Band Graphene Heterojunction Photodetectors with High Gain. ACS NANO 2023; 17:25037-25044. [PMID: 38096421 DOI: 10.1021/acsnano.3c07665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Graphene possesses an exotic band structure that spans a wide range of important technological wavelength regimes for photodetection, all within a single material. Conventional methods aimed at enhancing detection efficiency often suffer from an extended response time when the light is switched off. The task of achieving ultrafast broad-band photodetection with a high gain remains challenging. Here, we propose a devised architecture that combines graphene with a photosensitizer composed of an alternating strip superstructure of WS2-WSe2. Upon illumination, n+-WS2 and p+-WSe2 strips create alternating electron- and hole-conduction channels in graphene, effectively overcoming the tradeoff between the responsivity and switch time. This configuration allows for achieving a responsivity of 1.7 × 107 mA/W, with an extrinsic response time of 3-4 μs. The inclusion of the superstructure booster enables photodetection across a wide range from the near-ultraviolet to mid-infrared regime and offers a distinctive photogating route for high responsivity and fast temporal response in the pursuit of broad-band detection.
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Affiliation(s)
- Meng-Yu Tsai
- Institute of Electronics Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
- Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan
| | - Tsung-Han Tsai
- Institute of Electronics Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | | | - Hsueh-Lung Lu
- Institute of Electronics Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Jia-Xin Li
- Institute of Electronics Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Po-Liang Chen
- Institute of Electronics Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Kai-Wen Chen
- Department of Materials Science & Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Sun-Zen Chen
- Center for Nanotechnology, Materials Science and Microsystem, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chia-Hao Chen
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Chang-Hua Liu
- Institute of Electronics Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yen-Fu Lin
- Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan
| | - Po-Wen Chiu
- Institute of Electronics Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
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