Electric-field dependence of electron emission from the deep-level oxygen defect in GaP.

Abstract

Deep-level transient spectroscopy (DLTS) is shown to reveal a strong field dependence of the thermal emission of electrons from the singly occupied state (${\mathit{O}}_{1}$) of the deep-level oxygen defect in GaP. Detailed data on this field dependence and its variation with temperature over the range 350--470 K are reported. The experimental results are analyzed in terms of the phonon-assisted tunneling model of Makram-Ebeid and Lannoo. Good agreement is found between experiment and theory for the entire range of measurements. The values for physical parameters, such as the Franck-Condon shift, obtained from this fit are compared with published results from luminescence spectroscopy and other techniques on oxygen and other defects in GaP. Our study suggests a reappraisal of the configuration-coordinate model of oxygen in GaP proposed by Henry and Lang.