Characterization of surface defects by means of laser-induced Ga⁰emission from GaP surfaces

Abstract

The authors have carried out high-sensitivity measurements of the emission of Ga0 neutrals from a clean GaP (110) surface induced by laser pulses of subgap photon energies. They found that, below a sharp threshold laser fluence for evolution of surface damage, the emission yield of Ga0 atoms decreases, following two exponential functions, with repeating pulses of the same fluence. These two decays are ascribed to the ejection initiated by defects of two different types. These measurements are shown to be useful for characterizing defects of extremely small concentration.