Composition, structure, semiconductor properties of chemically deposited SnSe films

High adhesion tin monoselenide SnSe layers with a thickness of up to 200 $\pm$ 10 nm have been prepared by hydrochemical deposition from a trilonate reaction mixture. It was revealed by the X-ray diffraction method that the synthesized films crystallize in the orthorhombic system (S. G. Pnma). The presence of a significant amount of oxygen in the surface layers of the films is explained by partial oxidation of the samples with the formation of the SnO$_2$ phase. The results of ion etching to a depth of 18 nm showed a sharp decrease in the oxygen content with depth and actual correspondence of the elemental composition to SnSe. According to the results of optical studies, the band gap was found to be 1.69 eV for direct type of transitions, respectively. The synthesized SnSe layers have a hole-type conductivity typical of this material.