Carrier mobilities in heavily doped pseudomorphic Ge1-x Snx-epilayers

This work reports on the carrier mobilities in heavily doped, pseudomorphically grown Ge 1-x Sn x -epilayers with Sn-concentrations up to 9.2%. For this purpose, Ge 1-x Sn x -alloys were grown on a relaxed Ge virtual substrate on top of a commercial Si (100) wafer using molecular beam epitaxy. The crystal structure and quality of the Ge 1-x Sn x -epilayers were analyzed by high-resolution X-ray diffraction. In order to extract the carrier mobilities in Ge 1-x Sn x , low temperature hall measurements were carried out, using a Van-der-Pauw-geometry. It is shown that with increasing Sn-concentration we find a decrease in carrier mobility, which corresponds to an increasing sheet resistance.