Thin films of n-type SnSe2 produced from chemically deposited p-type SnSe

Abstract Tin(IV) selenide (SnSe 2 ) thin films 120–280 nm in thickness are obtained through heating SnSe films at 350 °C, in the presence of Se-vapor. Thin film of SnSe deposited from a chemical bath is of orthorhombic crystal structure, with a band gap, E g , of 0.94 eV, and p-type conductivity of 0.3 Ω − 1 cm − 1 . Thin film of SnSe 2 280 nm in thickness of hexagonal crystalline structure, with E g of 1.2 eV and n-type electrical conductivity of 2 Ω − 1 cm − 1 is produced from SnSe film 260 nm in thickness. The SnSe 2 film shows a Hall mobility of 10 cm 2 /(V s), carrier (electron) concentration 10 17 –10 18 cm − 3 and thermoelectric power of − 390 μV/K. The thin film of SnSe 2 formed this way is stable during further heating at temperatures up to 430 °C, but it reverts to p-type SnSe thin film when heated at 530 °C. Applications of these SnSe and SnSe 2 thin films are considered.