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Photoconductive Properties of GaAs1−xNx Double Heterostructures as a Function of Excitation Wavelength

Published online by Cambridge University Press:  10 February 2011

R. K. Ahrenkiel
Affiliation:
National Renewable Energy Laboratory
A. Mascarenhas
Affiliation:
National Renewable Energy Laboratory
S. W. Johnston
Affiliation:
National Renewable Energy Laboratory
Y Zhang
Affiliation:
National Renewable Energy Laboratory
D. J. Friedman
Affiliation:
National Renewable Energy Laboratory
S. M. Vernon
Affiliation:
Spire Corporation
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Abstract

The ternary semiconductor GaAs1−xNx with 0 < x < 0.3 can be grown epitaxially on GaAs and has a very large bowing coefficient. The alloy bandgap can be reduced to about 1.0 eV with about a 3% nitrogen addition. In this work, we measlired the internal spectral response and recombination lifetime of a number of alloys using the ultra-high frequency photoconductive decay (UHFPCD) method. The data shows that the photoconductive excitation spectra of the GaAs0.97N0.03 alloy shows a gradual increase in response through the absorption edge near Eg. This contrasts with most direct bandgap semiconductors that show a steep onset of photoresponse at Eg. The recombination lifetimes frequently are much longer than expected from radiative recombination and often exceeded 1.0 µs. The data was analyzed in terms of a band model that includes large potential fluctuations in the conduction band due to the random distribution of nitrogen atoms in the alloy.

Type
Research Article
Copyright
Copyright © Materials Research Society 2000

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