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Title: Role of self-trapped holes in the photoconductive gain of β-gallium oxide Schottky diodes

Solar-blind photodetection and photoconductive gain > 50 corresponding to a responsivity > 8 A/W was observed for β-Ga 2O 3 Schottky photodiodes. We investigated the origin of photoconductive gain. Current-voltage characteristics of the diodes did not indicate avalanche breakdown, which excludes carrier multiplication by impact ionization as the source for gain. However, photocapacitance measurements indicated a mechanism for hole localization for above-band gap illumination, suggesting self-trapped hole formation. Comparison of photoconductivity and photocapacitance spectra indicated that self-trapped hole formation coincides with the strong photoconductive gain. We conclude that self-trapped hole formation near the Schottky diode lowers the effective Schottky barrier in reverse bias, producing photoconductive gain. Ascribing photoconductive gain to an inherent property like self-trapping of holes can explain the operation of a variety of β-Ga 2O 3 photodetectors.
Authors:
 [1] ;  [1] ;  [2] ; ORCiD logo [2] ;  [2]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. Auburn Univ., AL (United States). Department of Physics
Publication Date:
Report Number(s):
SAND-2016-2312J
Journal ID: ISSN 0021-8979; JAPIAU; 621965
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 119; Journal Issue: 10; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY
OSTI Identifier:
1249076
Alternate Identifier(s):
OSTI ID: 1421089

Armstrong, Andrew M., Crawford, Mary H., Jayawardena, Asanka, Ahyi, Ayayi, and Dhar, Sarit. Role of self-trapped holes in the photoconductive gain of β-gallium oxide Schottky diodes. United States: N. p., Web. doi:10.1063/1.4943261.
Armstrong, Andrew M., Crawford, Mary H., Jayawardena, Asanka, Ahyi, Ayayi, & Dhar, Sarit. Role of self-trapped holes in the photoconductive gain of β-gallium oxide Schottky diodes. United States. doi:10.1063/1.4943261.
Armstrong, Andrew M., Crawford, Mary H., Jayawardena, Asanka, Ahyi, Ayayi, and Dhar, Sarit. 2016. "Role of self-trapped holes in the photoconductive gain of β-gallium oxide Schottky diodes". United States. doi:10.1063/1.4943261. https://www.osti.gov/servlets/purl/1249076.
@article{osti_1249076,
title = {Role of self-trapped holes in the photoconductive gain of β-gallium oxide Schottky diodes},
author = {Armstrong, Andrew M. and Crawford, Mary H. and Jayawardena, Asanka and Ahyi, Ayayi and Dhar, Sarit},
abstractNote = {Solar-blind photodetection and photoconductive gain > 50 corresponding to a responsivity > 8 A/W was observed for β-Ga2O3 Schottky photodiodes. We investigated the origin of photoconductive gain. Current-voltage characteristics of the diodes did not indicate avalanche breakdown, which excludes carrier multiplication by impact ionization as the source for gain. However, photocapacitance measurements indicated a mechanism for hole localization for above-band gap illumination, suggesting self-trapped hole formation. Comparison of photoconductivity and photocapacitance spectra indicated that self-trapped hole formation coincides with the strong photoconductive gain. We conclude that self-trapped hole formation near the Schottky diode lowers the effective Schottky barrier in reverse bias, producing photoconductive gain. Ascribing photoconductive gain to an inherent property like self-trapping of holes can explain the operation of a variety of β-Ga2O3 photodetectors.},
doi = {10.1063/1.4943261},
journal = {Journal of Applied Physics},
number = 10,
volume = 119,
place = {United States},
year = {2016},
month = {3}
}