Abstract
We present the results of experimental determination of the fundamental band gap () and the spin-orbit split-off energy gap () of zinc-blende CdSe using photomodulation spectroscopy. The single-crystal CdSe film was grown by molecular-beam epitaxy on a (100) GaAs substrate with a ZnTe buffer layer. Photoreflectance (PR) measurements were performed on the sample at various temperatures from 10 K to room temperature. The sharp derivativelike spectral features associated with the interband and transitions in PR spectra allow us to determine the and + band-gap energies. We found that zinc-blende CdSe has a fundamental band gap of 1.661 eV and a spin-orbit split-off gap of 0.42 eV at room temperature (295 K). The fundamental band gap of zinc-blende CdSe has been mapped out as a function of temperature and the Varshni thermal coefficients have been determined for this material. The results yield (T)=1.766–6.96× /(281+T) eV.
- Received 6 May 1994
DOI:https://doi.org/10.1103/PhysRevB.50.8012
©1994 American Physical Society