Investigation of the Optical Properties of InSb Thin Films Grown on GaAs by Temperature-Dependent Spectroscopic Ellipsometry

Abstract

InSb thin films were grown on GaAs substrates by metal organic chemical vapor deposition (MOCVD) and investigated by temperature-dependent spectroscopic ellipsometry (TD-SE). The refractive index, extinction coefficient, and dielectric function of the InSb films were extracted. The variation of critical point energies (E1, E1+Δ1, E2, $$ {E}_1^{\hbox{'}} $$ ) related to the excited state transitions of InSb and the second energy derivatives of the dielectric function at different temperatures showed that the InSb thin film had high electrical and optical stability at the evaluated temperatures. TD-SE analysis revealed a temperature range suitable for the use of InSb/GaAs-based devices. Beyond 250°C, InSb was heavily oxidized to form a thin In-O layer, causing a pronounced change in the optical constants. The results indicated that optimized InSb thin films grown on GaAs by MOCVD possess good optical and structural properties.