Band gap measurement of Si(sub 1-x)C(sub x)/Si (0(le)x(le)0.014) alloys using photoluminescence and spectroscopic ellipsometry

摘要

The authors have characterized the optical properties of heteroepitexial Si(sub 1-x)C(sub x)/Si (0(le)x(le)-0.014) alloys grown on Si substrates by solid phase epitaxy using spectroscopic ellipsometry and photoluminescence. The measured dielectric function confirms that the samples are of good crystalline quality. The 14-K photoluminescence spectra of Si(sub 1-x)C(sub x)/Si show several defect peaks. After hydrogen passivation, the authors observed a new peak near 1.15-1.17 eV which increases in energy with the incorporation of carbon. The authors tentatively assign this peak as the no-phonon peak of the Si(sub 1-x)C(sub x) epi-layer. They discuss the alloy shift of the observed spectroscopic features in terms of the C-induced change in the Si indirect band gap.