Polarized cathodoluminescence induced by low-energy spin-polarized electrons injected in p-GaAs(Cs,O)

We report on the experimental study of polarized cathodoluminescence induced by low-energy spin-polarized electrons injected into a semiconductor. A beam of polarized electrons was prepared by emission of optically oriented electrons from p-GaAs(Cs,O) negative electron affinity photocathode. The beam was injected in a p-GaAs target, which was also activated by cesium and oxygen in order to reduce the work function. The target was cooled down to T∼100K. By varying the electrical bias it was possible to vary the kinetic energy of the injected electrons in the conduction band of the target. The radiative recombination of the injected spin-polarized electrons resulted in circularly polarized cathodoluminescence with relatively high intensity and degree of polarization for low electron energies in the region of 1-5 eV. The prospects of a low-energy electron spin polarimeter based on light detection is discussed.