Cu2ZnSnSe4 films from binary precursors

The precursor stacked films of consistent binary chalcogenides (ZnSe, SnSe, CuSe) were deposited onto molybdenum covered soda-lime glass substrates by vacuum evaporation. Thermal treatments in SnSe2 or elemental selenium containing atmospheres were used for copper-zinc-tin-sulphide (CZTSe) formation. XPS investigations confirm the formation of CZTSe films homogeneous in bulk in both selenization atmospheres. At the same time, surface area composition of films selenized in Se and SnSe2 differed and the surface layer of CTZSe films selenized in SnSe2 atmosphere was tin-rich, containing separate phases of Se and SnSe2. The etching of CZTSe films with 1% Br-2-MeOH (bromine in methanol) at the rate of 75 nm/s removed mainly metals from the surface films and left precipitates of Se on the surface. Solar cell structures with the efficiency of about 3% were developed using selenized and etched films. (C) 2013 AIP Publishing LLC.