Transport properties of SnTe_xSe_1-x thin films

Abstract

The ternary semiconductors SnTe<i>_x</i>Se_1-x, (where 0≤ <i>x </i>≤1<i>), </i>were prepared by fusion method. The SnTe_xSe_1-x thin films were prepared by thermal evaporation under vacuum of about 10^-5 Torr. The structure and the composition analysis of SnTe_xSe_1-x in powder and this films form were investigated by X-ray diffraction and microprobe analysis technique respectively. It was found that the electrical conductivity σ increases, while the activation energy decreased with increasing composition (<i>x</i>). The thermoelectric power and Hall voltage measurements indicated that the SnTe_xSe_1-x thin films were P-type conduction. The SnTe_xSe_1-x thin films were non-degenerate semiconductor for all values of <i>x</i> from zero to 0.8 while for SnTe (<i>x</i>=1) the films were degenerate and had a metallic behaviour. Moreover the carrier density <i>P </i>was changed from~10¹⁷<i> </i>to 10²¹cm^-3 as changed from zero to one. It was found that the mobility of SnTe_xSe_1-x thin films increased as <i>x</i> increased, which indicated the presence of two types of scattering mechanisms, namely ionized impurity scattering as well as grain boundary potential barrier scattering. The effective mass <i>m</i> of SnTe_xSe_1-x thin films were found to increase with composition <i>x.</i>