Selective excitation luminescence in bulk-grown GaAs

Abstract

We have measured the excited state levels of two different shallow acceptors in bulk-grown GaAs, using selective excitation luminescence. The 1S–2S energy differences were measured to be 21.5 and 18.5 meV, respectively. By comparing these values to those measured by two-hole transition luminescence in high quality epitaxial GaAs [Ashen et al., J. Phys. Chem. Solids 36, 1041 (1975)], the acceptors were identified as Zn and C. The measured 1S–2P energy differences also support the identification. These studies demonstrate that selective excitation luminescence can be used to identify shallow acceptors in bulk-grown semi-insulating GaAs, and hence can be used as a diagnostic tool for bulk-grown samples.