Localized vibrational modes of Li defect complexes in GaAs

Abstract

Li defects created in GaAs by high-temperature Li diffusion were studied via their IR-active localized vibrational modes. In an exploratory series of experiments the effects of varying the Li diffusion conditions on the localized vibrational mode spectrum were studied. The variables included (i) the diffusion temperature, (ii) initial doping of the GaAs, and (iii) the Li isotope in a series of sequential high- and low-temperature diffusions. It was concluded that the Li defects consist of Li complexed with native defects created during the diffusion heat treatment and stabilized by the Li. Detailed measurement and analysis of spectra due to Li isotope mixtures yielded the numbers of Li atoms/complex and Li site equivalences.