Structural and optical characterization of Sn-Se system semiconductor synthesized by solid state reaction

A multiphase nanocrystalline material was obtained by solid state reaction from binary mixtures of elemental Sn and Se powders in 46 hours of high energy milling. The existence of three crystalline phases, the orthorhombic SnSe, the hexagonal SnSe₂ and the tetragonal rutile-type SnO₂, was revealed through X-ray diffraction (XRD) and Rietveld structural refinement. At 40 hours of reaction, the proportion of each structural phase was 33.3wt%. The single line method was applied to obtain the apparent crystallite size. The Raman modes in the low-frequency were attributed to orthorhombic-SnSe and hexagonal-SnSe₂ phases. The high-frequency region was activated by tetragonal-SnO₂ phase. (author)