A. Krotkus et al., ULTRAFAST PHOTOCONDUCTORS FROM LOW-TEMPERATURE MOCVD-GROWN GAAS AND INGAAS EPITAXIAL LAYERS, Applied physics. A, Solids and surfaces, 58(2), 1994, pp. 177-181
GaAs and InGaAs epitaxial layers were grown by Metal-Organic Chemical
Vapor Deposition at Low substrate Temperatures (LT-MOCVD). The layers,
grown at temperatures below 430 degrees C were semi-insulating. Trans
mission electron microscopy images reveal uniformly distributed 3-10 n
m size clusters which consist, most probably, of zinc. Photodetectors
fabricated from those layers feature nonlinear photocurrent versus opt
ical power dependence. The nonlinearities are explained in terms of el
ectric field redistribution. The nonlinear photoconductive correlation
measurements show that excess carrier lifetimes are in the range of 2
0-50 ps.