Deep-Level Luminescence of Cr-Doped GaAsP Alloys

Deep-level photoluminescence spectra of Cr-doped GaAsP alloys have been measured systematically over the whole composition range. It has been found that the Cr-related luminescence spectra of GaAs1-x P x :Cr alloys exhibit only a broad band without the well-known characteristic sharp zero-phonon line as in GaAs and GaP, and the peak position is nearly unchanged with respect to the alloy composition below the phosphorus composition of x∼0.65. Moreover the halfwidth of the Cr-related band is larger in GaAsP than in GaAs and GaP. Luminescence-excitation data indicate that the below-gap excitation is dominant in GaAsP alloys.