Optical properties of InSb and its electrochemically grown anodic oxide

Abstract

Ellipsometrically determined complex dielectric-function data have been obtained for InSb and its electrochemically grown anodic oxide at room temperature from 1.5-6.0 eV. Our data for InSb are a clear improvement over the earlier data of Philipp and Ehrenreich. The critical-point energies of the ${E}_{1}$ and ${E}_{1}+{\ensuremath{\Delta}}_{1}$ transitions are determined to be 1.872\ifmmode\pm\else\textpm\fi{}0.002 eV and 2.374\ifmmode\pm\else\textpm\fi{}0.010 eV, respectively. The oxide has an intrinsic absorption threshold at 3.8 eV, near that of ${\mathrm{In}}_{2}$${\mathrm{O}}_{3}$. However, substantial absorption, probably due to the presence of elemental Sb, is found below this threshold in these films.