Tailoring of transport dynamics by recombination center engineering of co

摘要

Abstract: rt recent subnanosecond photoconductive measurements on a p-i-n device made from a copper-compensated silicon-doped semi- insulating GaAs (GaAs:Si:Cu) substrate. Photoconductivity in this relatively large volume device (0.05 $MUL 0.5 $MUL 1.0 cm$+3$/) is generated by extrinsic absorption of a 1-$mu@m laser pulse, and optically quenched with a 2-$mu@m laser pulse. It is shown experimentally that these large, high-power (multimegawatt) switches have the potential to switch subnanosecond pulses when a copper-compensated GaAs material with suitable fast electron- hole-pair recombination rate is engineered. Test and evaluation of BOSS devices with subnanosecond switching performance is reported. In one case, observation of an electron-hole pair recombination time constant of 0.25 ns is reported in GaAs:Si:Cu irradiated with a neutron dose of 1.8 $MUL 10$+15$/ cm$+$MIN@2$/, a factor of seven faster than previously reported.!15