Temperature Dependence of Photoluminescence in Cadmium-Doped Epitaxial GaAs

Abstract

The relative photoluminescence intensities of band‐to‐band and band‐to‐acceptor radiative recombination were measured as a function of temperature. p‐Type cadmium‐doped epitaxial GaAs was studied. The samples that were used had carrier concentrations in the range of 5×10¹⁷ to 3.5×10¹⁶/cc as determined from Hall measurements at 300°K. Over the temperature range 40° to 150°K the two emission peaks were sufficiently resolved so that accurate intensity measurements could be made. The temperature dependence of the band‐to‐acceptor luminescence intensity is in agreement with theoretical estimates of the inverse lifetime for this recombination mechanism. The variation of the diffusion of photoexcited minority carriers as a function of temperature must be considered in order to relate the band‐to‐band luminescence with the lifetime for the mechanism. Minority carrier diffusion theory analysis suggests that the good agreement obtained between theory and experiment for the band‐to‐acceptor luminescence occurs because the total lifetime and the diffusion coefficient have similar temperature dependence in the temperature range studied.