A. G. U. Perera, S. G. Matsik, M. Ershov,
Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303
Y. W. Yi, H. C. Liu, M. Buchanan, Z. R. Wasilewski
Institute for Microstructural Sciences, National Research Council, Ottawa, Canada
ABSTRACT
In this work,
experimental results showing very slow (up to 104 seconds) dark
current transients in n-type GaAs/Al0.27Ga0.73As quantum
well photodetectors (QWIPs) are reported. The transients with amplitudes of
0.1% to 65% of the steady state current have been observed at 77 K. These
effects are believed to be associated with initially ionized deep levels acting
as traps reducing the positive charge in the structure. The time constant of
the dark current (transient) decreases with increasing temperature with an
experimentally determined activation energy ~75 meV. A fitting of the capture
cross section to s(T) = s0exp(Ec/kBT) gives an
estimate for the capture activation energy of Ec ~ 35meV. ©
2000 Elsevier Science B.V. All Rights Reserved.
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