MSELD SnS1−xSex alloy thin films towards efficient structural and bandgap engineering for photonic devices

Ternary SnS1−xSex alloy thin films prepared by depositing stacks of varied elemental weight percentages using multisource sequential elemental layer deposition (MSELD) technique. The focus of investigation is to achieve SnS1−xSex phase by varying ‘Se’ constituent in the film for large scale photovoltaic (PV) devices. The substitution of varied ‘Se’ weight percentages leads to the formation of ternary SnS1−xSex phases along with the presence of changed polytypic SnxSy phases causing structural deformations. These structural deformations leads to variation in unit cell volume and axis strain due to insertion of higher atomic radii of selenium (‘Se’) in place of Sulphur (‘S’). This structural engineering results into variation of direct–indirect bandgaps, higher absorption and excellent electrical properties viz. resistivity (4.5–66.9 Ωcm), mobility (1.8–9.8 cm2/Vs) and carrier concentration (~ 1016 to 1017 cm−3) for their use as photosensitive layer in the development of large scale photonic devices.