Kinetics of highly spin-polarized electron photoemission from an InGaAlAs strained layer by energy and spin-resolved measurements

High-resolution energy distribution curves and spin polarization versus energy distribution curves from an AlInGaAs layer, capped by a heavily doped thin GaAs quantum well layer has been measured. Polarization P of up to 83% in conjunction with quantum yield Y=0.5% at T=130 K has been obtained. These results are compared to polarization and quantum yield spectra at high excitation power. The narrow-band quantum well is shown to provide large effective negative electron affinity values with no harm to electron polarization. The studies in linear and nonlinear excitation regimes bring insight into the kinetics of photoemission and favor the photoemission model with elastic electron tunneling through the surface barrier. © 2003 American Institute of Physics.