Circular Polarization of Photoluminescence Excitation Spectra of Strained GaAs Layer

Abstract
Measurements of photoluminescence (PL) spectra and photoluminescence excitation (PLE) spectra were made on strained GaAs samples fabricated as a photocathode of spin-polarized electron source. PL and PLE due to the interband transition of the strained GaAs layer showed large polarization in comparison with those of the GaAs substrate. The increase of the hand gap and the splitting of the valence band were observed in luminescence polarization spectra of PLE although they are not clear in the original spectra. The spin polarization of conduction band electrons in the case of resonant excitation was estimated to be 72% from luminescence polarizations of PL and PLE spectra.