A STUDY OF SUPER-BANDGAP TIME-RESOLVED LUMINESCENCE IN INP

Super-bandgap time-resolved photoluminescence is used to measure the t ransport properties of a degenerate electron-hole gas in InP. It is fo und that the luminescence decay at energies above the energy gap is go verned by the shift of the electron quasi-fermi level to lower energie s; this shift is due to a change in the excess carrier concentration a s a result of diffusion perpendicular to the crystal surface. The resu lts are analysed using a transport model based on the Fermi-Dirac carr ier statistics and non-parabolic conduction band structure; the effect of these factors on the time-resolved and energy-resolved luminescenc e spectra is examined. It is found that the perpendicular carrier tran sport affects the energy-resolved spectra in a similar way to carrier energy loss processes. This implies that analysis of carrier cooling r ates based on time-resolved photoluminescence experiments must take in to account transport phenomena.