Composition, Structure, and Semiconductor Properties of Chemically Deposited SnSe Films

Highly adhesive tin-monoselenide (SnSe) layers (200 +/- 10) nm thick are grown by hydrochemical deposition from a trilonate reactive mixture. X-ray diffraction shows that the synthesized films crystallize in the orthorhombic system (space group Pnma). The significant oxygen content in the film surface layers is explained by the partial oxidation of samples with SnO2 phase formation. The results of ion etching to a depth of 18 nm show a sharp decrease in the oxygen content over thickness and real correspondence to the SnSe elemental composition. The band gap determined by optical studies for direct transitions is 1.69 eV. The synthesized SnSe layers exhibit p-type conductivity, which is characteristic of this material.