Preparation and Characterization of Vacuum Evaporated SnSe and SnSe_2 Multilayer Thin Films

摘要

Tin selenide multilayer thin films were prepared by successive evaporation of tin and selenium layers. The X-ray diffraction study reveals that as deposited films (SnSe) have orthorhombic crystal structure while the annealed films (SnSe_2) have hexagonal structure. The shift in absorption spectra was observed on SnSe_2 films from UV studies. The optical band gap values of SnSe_2 and SnSe are found to be 1.3 eV and 2.8 eV respectively. The emission peaks from room temperature photoluminescence spectra are related with the optical band gap of the films. The room temperature electrical resistivity of SnSe film is found to be higher than SnSe_2 film and the resistivity as a function of temperature has also been studied. The thermal activation energy of the prepared films is found to in the range of 0.52-0.74 Ω-cm.