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Title: Hydrostatic and uniaxial stress dependence and photo induced effects on the channel conductance of n-AlGaN/GaN heterostructures grown on sapphire substrates

Abstract

The authors measure the hydrostatic stress, uniaxial stress, and photo induced dependence of the channel conductance of two-dimensional electron gas AlGaN/GaN heterostructures grown on c-axis sapphire. The structures examined are grown by nitrogen-plasma molecular beam epitaxy and metal organic chemical vapor deposition. Electrical conductance measurements are made with four point probes on Hall bar samples. Both, hydrostatic stress and uniaxial stress result in changes in the conductance. moreover, these changes in conductance have long settling times after the stress is applied and may be due to deep level defects, the energy levels of which change with stress. Stress coefficients extracted from the samples are partially attributed to deep level defects and to the piezoelectric effect resulting from different piezoelectric coefficients of GaN and AlN. Photo induced changes of the two-dimensional electron gas are also observed. They find that pulsed illumination produces long transient times in the conductance. These transients are reduced by thermal heating in some samples. However, they can still be present at 153 C.

Authors:
; ;  [1]
  1. and others
Publication Date:
Research Org.:
Univ. of Minnesota, Minneapolis, MN (US)
Sponsoring Org.:
National Science Foundation (NSF); US Department of the Navy, Office of Naval Research (ONR)
OSTI Identifier:
20104752
Resource Type:
Conference
Resource Relation:
Conference: 1999 Materials Research Society Spring Meeting, San Francisco, CA (US), 04/05/1999--04/08/1999; Other Information: PBD: 1999; Related Information: In: Wide-band semiconductors for high-power, high-frequency and high-temperature applications -- 1999. Materials Research Society symposium proceedings: Volume 572, by Binari, S.C.; Burk, A.A.; Melloch, M.R.; Nguyen, C. [eds.], 575 pages.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; N-TYPE CONDUCTORS; HETEROJUNCTIONS; ALUMINIUM NITRIDES; GALLIUM NITRIDES; ELECTRIC CONDUCTIVITY; STRESSES; ELECTRON GAS

Citation Formats

Fung, A.K., Cai, C., and Ruden, P.P. Hydrostatic and uniaxial stress dependence and photo induced effects on the channel conductance of n-AlGaN/GaN heterostructures grown on sapphire substrates. United States: N. p., 1999. Web.
Fung, A.K., Cai, C., & Ruden, P.P. Hydrostatic and uniaxial stress dependence and photo induced effects on the channel conductance of n-AlGaN/GaN heterostructures grown on sapphire substrates. United States.
Fung, A.K., Cai, C., and Ruden, P.P. Thu . "Hydrostatic and uniaxial stress dependence and photo induced effects on the channel conductance of n-AlGaN/GaN heterostructures grown on sapphire substrates". United States.
@article{osti_20104752,
title = {Hydrostatic and uniaxial stress dependence and photo induced effects on the channel conductance of n-AlGaN/GaN heterostructures grown on sapphire substrates},
author = {Fung, A.K. and Cai, C. and Ruden, P.P.},
abstractNote = {The authors measure the hydrostatic stress, uniaxial stress, and photo induced dependence of the channel conductance of two-dimensional electron gas AlGaN/GaN heterostructures grown on c-axis sapphire. The structures examined are grown by nitrogen-plasma molecular beam epitaxy and metal organic chemical vapor deposition. Electrical conductance measurements are made with four point probes on Hall bar samples. Both, hydrostatic stress and uniaxial stress result in changes in the conductance. moreover, these changes in conductance have long settling times after the stress is applied and may be due to deep level defects, the energy levels of which change with stress. Stress coefficients extracted from the samples are partially attributed to deep level defects and to the piezoelectric effect resulting from different piezoelectric coefficients of GaN and AlN. Photo induced changes of the two-dimensional electron gas are also observed. They find that pulsed illumination produces long transient times in the conductance. These transients are reduced by thermal heating in some samples. However, they can still be present at 153 C.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1999},
month = {7}
}

Conference:
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