LOCAL HYDROGEN AND DEUTERIUM VIBRATIONAL MODES IN Si-DOPED GaAs

Abstract

Infrared absorption on GaAs doped with the isotopes of silicon under hydrogen or deuterium plasma treatment has shown the presence of two new localized modes, all in the range of 625–1725 cm-1. We present a simple nine-atom molecular model to compute these defect modes by assuming the hydrogen or deuterium to be bound in the antibonding position of the substituted Si atom, resulting in a defect complex of C3V symmetry. The two new vibrational modes of the paired Si are found with a small isotope shift, when H is replaced by D. Group theoretical methods are employed for the precise identification of the localized modes.