SPIN-DIFFUSION OF OPTICALLY ORIENTED ELECTRONS AND PHOTON ENTRAINMENTIN N-GALLIUM ARSENIDE

An experimental and theoretical study of spin transport in the n-GaAs semiconductor is reported. Transport of average electron spin from the photoexcited crystal surface is shown to be determined by the spin di ffusion process. At the same time the transport of photoexcited carrie rs takes place primarily through photon entrainment, which transfers n onequilibrium carriers into the bulk of the semiconductor to distances considerably in excess of the electron spin diffusion length. A compa rison of the experimental results with theory permits one to determine the average-spin diffusion length and electron-spin relaxation time. (C) 1997 American Institute of Physics.