Photo-Induced Reversible Modification of II-VI Semiconductor Surface Composition and Structure

Abstract

AbstractIt is shown that the composition and structure of CdTe and CdS surfaces can be reversibly controlled by excimer laser irradiation at fluences below the melting threshold. The removal rate is observed to depend exponentially on laser fluence up to the melting threshold. The translational energies of products desorbed from laser-irradiated CdTe surfaces were determined using time-of-flight spectrometry and are well-described by a Maxwellian velocity distribution. The dynamics of the photo-stimulated desorption process are correlated with the laser-induced changes in composition, and it is shown that the data are consistent with a thermal mechanism for desorption. A model is introduced which describes the reversible, fluence-dependent changes in composition and structure in terms of the kinetic competition between formation and desorption processes at the semiconductor surface.