We have studied the influence of misfit dislocations on hole accumulation in the base layer of an n-AlGaAs/p-GaAs/n-InGaAs heterojunction phototransistor (HPT). Spatially and temporally resolved cathodoluminescence (CL) measurements reveal that variations in the hole accumulation is caused primarily by strain-induced defects which impede the transport of holes in the collector. The lifetime of holes in the InGaAs/GaAs collector is found to be negligibly affected by the underlying misfit dislocations in the InGaAs/GaAs collector. The reduction in the local electron-beam-induced current signal by the dislocations is less than ∼20%, indicating that these defects have a minor impact on the overall device performance.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)