The Picosecond Time Scale Spin-Polarized Electron Kinetics In Thin Semiconductor Layers

Time resolved photoemission of highly spin-polarized electrons from thin strained and unstrained GaAsxP1-x films of various thicknesses has been investigated. An upper limit for the response time of a photocathode has been found to be 1 ps for layer thicknesses less than 150 nm. We show that the electron depolarization during the electron extraction to the surface band bending region can be as low as 2% while the losses in the band bending region can contribute to 4% spin relaxation.