Radiation Effects in Quantum Well Detectors
Final rept. 1 Oct 1997-30 Sep 1999
AIR FORCE RESEARCH LAB KIRTLAND AFB NM
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We performed photoluminescence PL measurements of interband transitions in InGaAsAlGaAs multiple quantum wells before and after fast neutron irradiation. It is shown that the intensity of the intersubband transitions is dramatically decreased in heavily irradiated samples, which can be explained in terms of trapping of the two-dimensional electrons by the irradiation induced defects. A negative persistent effect was also observed in the heavily irradiated samples. It is noted that the recovery of the electrons from this effect occurs at two temperature stages with thresholds at 104K and -250K, which indicates that the electrons were released from two different traps as the temperature is increased. We also investigated the effects of 1 MeV proton beam with doses ranging between 10 x 10exp 12 and 5.0 x 10exp 14sq cm on GaAsAlGaAs. It is observed that the total integrated area of the intersubband transitions are dramatically decreased as the irradiation dose is increased This reduction was interpreted as being due to the trapping of the two-dimensional electron gas by the irradiation-induced-defects. The total integrated areas of the intersubband transitions were studied as a function of irradiation doses for samples cut from wafers with structures containing either bulk or superlattice barriers. The results reveal that the intersubband transitions in samples with superlattice barriers degrade at a faster rate as compared to those transitions in samples with bulk barriers.
- Quantum Theory and Relativity