Threshold photoemission analysis of the surface reactions of triethylgallium and trimethylgallium on GaAs(100): A promising technique for kinetics studies

Abstract

The decomposition of triethylgallium and trimethylgallium on a As-stabilized GaAs(100) surface has been analyzed by near threshold photoemission. For T⩽200 °C, the negative photocurrent change induced by adsorption of these electron acceptor molecules is directly related to the coverage. The adsorbed diethylgallium species decompose very rapidly above 240 °C to adsorbed Ga atoms, resulting in a positive photocurrent change due to the lower work function of a Ga surface. The activation energy and preexponential factor of this decomposition reaction were derived independently in the temperature range 200–240 °C from the time dependence of the photocurrent emitted from the surface upon exposure to triethylgallium at saturated coverage.