The temperature dependence of in-plane transient photoconductivity in GaInAs/InP MQWs

Abstract

Transient photoconductivity has been used to study the recombination of free carriers in GaInAs/InP multiple quantum well material. The sublinear increase in the initial amplitude of the photoconductivity with excitation intensity is attributed to the carrier density dependence of the mobility. This nonlinearity is taken into account when the time constant associated with the decay of the free carriers is obtained from the photoconductive decays. For low excess carrier densities, in the non-degenerate regime, the recombination was consistent with a kinetic radiative recombination model which included free carriers, excitons and photon recycling. The time constants, deduced from the experimental data, were in good agreement with the temperature dependence predicted by the model. When the excess carrier density was high enough to make the material degenerate, the initial decay, while the material remained degenerate, was exponential with a relatively short time constant. Even when the wells were full there was no evidence of Auger recombination. An upper limit of 3*10-29 cm6 s-1 could therefore be placed on the Auger coefficient.