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

•Thin film n-SnSe2 from chemically deposited p-SnSe film•Both films maintain the conductivity type and band gap at 400 °C.•Thermoelectric and photovoltaic applications considered

Tin(IV) selenide (SnSe2) 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, Eg, of 0.94 eV, and p-type conductivity of 0.3 Ω− 1 cm− 1. Thin film of SnSe2 280 nm in thickness of hexagonal crystalline structure, with Eg 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 SnSe2 film shows a Hall mobility of 10 cm2/(V s), carrier (electron) concentration 1017–1018 cm− 3 and thermoelectric power of − 390 μV/K. The thin film of SnSe2 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 SnSe2 thin films are considered.