Our research is in the field of semiconductor materials. We specialize in optical properties— measured with techniques such as spectroscopic ellipsometry, Raman scattering, and photoconductivity—, but we cover many other fields of semiconductor physics, from structural to thermal properties. We take advantage of the extraordinary infrastructure for materials research at Arizona State University, which include some of the best characterization facilities worldwide, the expertise of a few hundred specialists in many areas of materials physics, and the synthesis of unique materials that are not available anywhere else. For the past ten years, for example, we have investigated new semiconductor materials in which Sn is added to the traditional semiconductors Si and Ge. This work, prompted by the discovery of new synthetic routes by ASU researchers, has ignited a new field in semiconductor science in which ASU continues to play a leading role.