Minority-carrier lifetime study of the pressure induced Γ-X 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.