Minority-carrier lifetime study of the pressure induced Γ-<i>X</i> crossover in GaAs

Abstract

Room-temperature continuous and time-resolved (on a nanosecond scale) photoluminescence experiments have been performed on p-type GaAs. Observation of indirect luminescence in GaAs above 4 GPa allowed a direct determination of the room-temperature pressure coefficient of the Xc1 valleys. A new set of pressure dependence parameters for both Γ and X energy gaps in GaAs has been determined. These pressure coefficients, together with the intensity of luminescence as a function of pressure, yielded an estimate of the electron lifetime ratio confirmed by subsequent time-resolved experiments. A threefold enhancement of electron lifetime is observed above the Γ-X crossover.