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Title: Persistent photoconductivity in AlGaN/GaN heterojunction channels caused by the ionization of deep levels in the AlGaN barrier layer

Time-dependent responses of drain current (I{sub d}) in an AlGaN/GaN HEMT under UV (3.3 eV) and red (2.0 eV) light illumination have been studied at 300 K and 250 K. UV illumination enhances I{sub d} by about 10 %, indicating that the density of two-dimensional electrons is raised by about 10{sup 12} cm{sup −2}. When UV light is turned off at 300 K, a part of increased I{sub d} decays quickly but the other part of increment is persistent, showing a slow decay. At 250 K, the majority of increment remains persistent. It is found that such a persistent increase of I{sub d} at 250 K can be partially erased by the illumination of red light. These photo-responses are explained by a simple band-bending model in which deep levels in the AlGaN barrier get positively charged by the UV light, resulting in a parabolic band bending in the AlGaN layer, while some potion of those deep levels are neutralized by the red light.
Authors:
; ; ; ;  [1] ;  [2] ;  [3]
  1. Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya 468-8511 (Japan)
  2. Toyota Central R and D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan)
  3. Toyota Motor Corporation, 543 Kirigahora, Nishihirose-cho, Toyota, Aichi 470-0309 (Japan)
Publication Date:
OSTI Identifier:
22261965
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1566; Journal Issue: 1; Conference: ICPS 2012: 31. international conference on the physics of semiconductors, Zurich (Switzerland), 29 Jul - 3 Aug 2012; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DENSITY; ELECTRONS; GALLIUM NITRIDES; HETEROJUNCTIONS; PHOTOCONDUCTIVITY; TIME DEPENDENCE; TWO-DIMENSIONAL CALCULATIONS