Study of structural, optical and thermal properties of nanostructured SnSe2 prepared by mechanical alloying

A nanostructured SnSe2 phase was successfully produced by mechanical alloying. The influence of defect centers on the structural, optical and photoacoustic properties of the alloy was investigated by annealing the as-milled SnSe2 powder. From optical absorbance and photoacoustic absorption measurements, the energy band gap, E-g, and the thermal diffusivity, alpha, values were determined for as-milled and annealed samples. The thermal conductivity values for the as-milled and annealed samples were estimated by using the alpha values obtained from the photoacoustic measurements, the density values obtained from the Rietveld refinement of the X-ray diffraction patterns and the specific heat value for the bulk SnSe2 phase. These values were used to estimate the dimensionless figure of merit ZT. It was evidenced that the ZT parameter of the as-milled nanostructured SnSe2 sample is almost twice larger than the ZT of the annealed sample. (C) 2015 Elsevier B.V. All rights reserved.