Interference of Light- and Heavy-Hole Contributions to the Electroreflectance Spectrum of Germanium

Abstract

We have observed as many as 11 half oscillations in electroreflectance spectra of germanium at the direct edge (${{\ensuremath{\Gamma}}_{8}}^{+}\ensuremath{\rightarrow}{{\ensuremath{\Gamma}}_{7}}^{\ensuremath{-}}$) at room temperature. In addition, near the experimental sixth half oscillation where the light- and heavy-hole contributions are of opposite signs, we observe destructive interference which greatly modifies the signal line shape in that region. The experimental results also demonstrate that neither thermal broadening nor field inhomogeneity need be a problem in electroreflectance measurements.