Photo-carrier radiometry was applied to a semi-insulating GaAs wafer in order to detect and identify radiative defects. Due to the ultra-fast free carrier recombination lifetime, the conventional carrier-diffusion wave-based photo-carrier radiometry theory was modified so as to reflect the signal domination by trap emission and capture rates in the absence of diffusion. Defect photoluminescence with photon energies ranging from 0.7 to 1.24eV was collected and analyzed using photo-thermal temperature spectra and resonant (rate-window) detection combined with frequency scans. Five defect levels were identified self-consistently from the combined rate-window and photo-carrier radiometry phase data, and the temperature dependence of the defect photoluminescence quantum efficiency was determined through multi-parameter best fits of the photo-carrier radiometry rate theory to the experimental data.

Radiative Defect State Identification in Semi-Insulating GaAs using Photo-Carrier Radiometry. J.Xia, A.Mandelis: Semiconductor Science and Technology, 2009, 24[12], 125002