High Luminescence Polarization of InGaAs–AlGaAs Strained Layer Superlattice Fabricated as a Photocathode of Spin-Polarized Electron Source

Abstract

High circular luminescence polarization of 65% was observed in the InGaAs–AlGaAs strained layer superlattice which was fabricated as a spin-polarized electron source. The dependence of photoluminescence polarization on the excitation photon energy was well explained by the calculated band structure of the sample. The spin relaxation time and the lifetime of photo-generated electrons in the conduction band were determined from the experimental results of the time-resolved photoluminescence measurement. The spin polarization of conduction band electrons at the instant of excitation was determined to be 94% from the photoluminescence polarization, the lifetime and the spin relaxation time.