Hot carrier dynamics in a (GaInSb/InAs)/GaInAlAsSb superlattice multiple quantum well measured with mid-wave infrared, subpicosecond photoluminescence upconversion

Abstract

We have extended the technique of subpicosecond photoluminescence upconversion to the mid-wave infrared spectral region and have used this system to investigate the energy relaxation of hot, optically injected electron-hole pairs in a narrow-band-gap (2.32 μm) (GaInSb/InAs)/ GaInAlAsSb superlattice multiple quantum well. These and similar structures are currently of interest as the active region for mid-wave infrared diode lasers. The measurements demonstrate that carriers, which are injected with nearly 1 eV of excess energy, are well described by a hot, thermalized distribution in the wells within 2 ps after excitation. For a carrier density of 1017 cm−3, cooling by optical phonon emission is essentially complete 15 ps after injection. By fitting the time dependence of the carrier temperature, we estimate an effective carrier- optical-phonon scattering time of 1.2 ps.