This Focused Research Group (FRG) project explores energy applications of group-IV (Si, Ge) semiconductor materials incorporating Sn. The combination of Sn with Si and Ge may allow desirable structural and electronic properties with advantageous opportunities in photovoltaics and thermoelectricity. Fundamental studies of the Si-Ge-Sn system are planned for the specific purposes: a) designing multijunction solar cells with fully optimized band gaps; b) exploring the potential of the Si-Ge-Sn system for intermediate band photovoltaics; c) designing materials with dramatically enhanced impact ionization rates; d) fabricating structures with ultra-low thermal conductivities; and e) engineering enhanced Seebeck coefficients. The size of the compositional space being explored, combined with possible nanostructural arrangements for a given composition, benefit from a multidisciplinary FRG approach. Theoretical simulations will be used to identify the most promising structures which will be synthesized using CVD methods introducing new precursors and modifications as required. Electrical and contactless optical characterization methods will be employed.

The project addresses fundamental research issues in a topical area of electronic/photonic materials science having energy related technological relevance. Additionally, the project will include several education/outreach efforts: hosting a regional workshop "Semiconductors and Society" for high school pre-seniors to (i) research student perceptions of how science and engineering innovations impact high-tech products relying on semiconductors (ii) elucidate how intellectual innovations can impact future manufacturing technologies to preserve the semiconductor sector as the major high-technology industry in Arizona and (iii) increase student interest in science and engineering and encourage the pursuit of advanced education in related technical fields. Also, new courses in materials and solid-state chemistry will be developed at ASU with integrated simulation and experimental components. These will be included in the undergraduate curriculum of a newly established "Science Master's in Nanoscience" program. Teaching modules and workshop materials will also be developed and disseminated through the project's web page.