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

Tin(IV) selenide (SnSe2) thin films 120-280 nm in thickness are obtained through heating SnSe films at 350 degrees 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 Omega(-1) cm(-1). Thin film of SnSe2 280 nm in thickness of hexagonal crystalline structure, with E-g of 1.2 eV and n-type electrical conductivity of 2 Omega(-1) cm(-1) is produced from SnSe film 260 nm in thickness. The SnSe2 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 mu V/K. The thin film of SnSe2 formed this way is stable during further heating at temperatures up to 430 degrees C, but it reverts to p-type SnSe thin film when heated at 530 degrees C. Applications of these SnSe and SnSe2 thin films are considered. (C) 2015 Elsevier B.V. All rights reserved.