Heteroepitaxial growth on nanostructured silicon surfaces

"This Phase II SBIR research effort addresses several approaches aimed at minimizing lattice constant and thermal expansion mismatches during heteroepitaxial growth of thick (~ several microns) films on Si substrates. A major focus of the research effortwould be one valuation of sub-50-nm linewidth deeply etched one and two dimensional sub-micrometer periodic structures as compliant buffer layers between the epilayer and Si substrate. Silicon structures at extreme nanoscale dimensions exhibit distinctlydifferent physical properties than the bulk material. In particular, these structures have lower melting points, are flexible, and exhibit either tensile, or compressive strain. Growth on these types of structures is expected to alleviate thermalexpansion mismatch. Si/SiGe and GaAs epilayers will be grown on nanostructured Si and processed into solar cells in collaboration with Emcore Corporation. A successful outcome of Phase II research will find applications in a wide range of materialsystems."