Picosecond luminescence of AlxGa1-xAs and GaAs double quantum well structures under high pressure

Abstract

Abstract The time-resolved luminescence of an electron-hole plasma in Al0.36Ga0.64As was studied as a function of pressure. Application of hydrostatic pressure varies the energy separation between the conduction band minima at Г and X. The dependence of the intensity ratio of the zero-phonon line and the two phonon replicas on this energy separation shows that scattering from X to Г by alloy disorder is as effective as scattering by phonons. We have further studied the tunneling of electrons between two GaAs quantum wells (QW) of different thicknesses through an Al0.35Ga0.65As barrier. The lifetime of electrons in the narrow QW, which is limitd by electron tunneling into the wider QW, stays constant from 0 to 2.4 GPa, where it drops within 0.1 GPa from 140 ps to less than 7 ps. At this pressure the X-point energy of the barrier coincides with the electron level in the wider QW. We infer that tunneling occurs only via the Г states in the barrier and that X states become effective only when real-state trans...