Interaction of Cl 2 with GaAs(110) with and without laser irradiation

Abstract

We have studied the interaction of Cl 2 with a well-defined GaAs(110) surface under ultra-high vacuum conditions. When this surface is cooled to below 100 K, chlorine adsorbs dissociatively and in molecular form. Illumination of a Cl 2-covered surface at 85 K with 193 nm laser light causes desorption of Cl atoms and the formation of AsCl 3. Radiation at 351 nm forms a much smaller quantity of AsCl 3 and desorbed Cl flux. Irradiation with a 535 nm laser produces no effect. We suggest that the surface reaction, in the case of 193 nm, is initiated by Cl 2 dissociation through attachment of electrons, photoemitted from the substrate.