Photoelectrical characteristic of isotype N+-GaSb/n(0)-GaInAsSb/N+-GaAlAsSb type II heterojunctions

Abstract

Photoelectrical characteristics and energy diagrams have been studied for LPE grown isotype heterostructures lattice-matched to GaSb substrates. The photocurrent sign dependence on photon energy as a function of forward bias in isotype N+-GaSb/n(0)-GaInAsSb/N+-GaAIAsSb heterojunctions due to hole confinement at the type II interface is observed and discussed. This effect is due to modulation of the barrier transparency at the interface limiting the tunnel transitions of the conduction electrons and to the localization of photoholes in the potential well at the type II interface. The sign reversal of the photocurrent on photon energy as a function of applied voltage takes place only on the forward bias.