OPTICAL CHARACTERIZATION OF SI1-XCX SS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.014) SEMICONDUCTOR ALLOYS/

We have characterized the optical properties of heteroepitexial Si1-xC x/Si(0 less than or equal to x less than or equal to 0.014) alloys gro wn on Si substrates by solid phase epitaxy using spectroscopic ellipso metry and photoluminescence. The measured dielectric function confirms that the samples are of good crystalline quality. The 14-K photolumin escence spectra of Si1-xCx/Si show several defect peaks. After hydroge n passivation, we observed a new peak near 1.15-1.17 eV which in creas es in energy with the incorporation of carbon. We tentatively assign t his peak to the no-phonon peak of the Si1-xCx epi-layer. We discuss th e alloy shift of the observed spectroscopic features in terms of the C -induced change in the Si indirect band gap.