Photoluminescence has been observed at room temperature in phosphorus-dopedGe1-ySny/Si(100) alloys containing carrier densities in the 1-6 1019 cm-3 range. The emission intensity is one order of magnitude stronger than observed in similar undoped films, and the enhancement is consistent with theoretical predictions for doped-Ge like materials. The ratio Idir/Iind of direct over indirect gap emission is found to increase for high-Sn concentrations as a result of the reduced -L valley separation in Ge1-ySny alloys. These results confirm that alloying with Sn is a viable alternative to tensile strain as a tool to enhance direct-gap emission in Ge-like semiconductors.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)