Carrier lifetime saturation in InGaAs single quantum wells

Abstract

The carrier recombination rate in strained InGaAs-GaAs single quantum well lasers of varying potential depth, as determined by the well/barrier band offsets, is investigated both theoretically and experimentally. At higher current densities (J≥300 A cm-2), the carrier lifetime saturates. The saturation lifetime in the shallow well is considerably longer (τsat∼4.2 ns) than in the deep quantum wells (QWs) (τsat∼0.9 ns). The recombination rate law of bulk material is inadequate to predict the recombination rates in the InGaAs QWs. Consequently, a local recombination model has been developed which accurately predicts the lifetime saturation behavior observed in the QWs. Overall, it appears that an adequate model of carrier recombination is dependent both on material composition factors (i.e., accurate recombination coefficients) and on the detailed electron-hole densities which are influenced by structural factors such as QW potential depth and QW width.© 1995 American Institute of Physics.