SnTexSe1−x Alloy: An Effective Alternative to SnSe Nano-crystalline Thin Films for Optoelectronic Applications

As prepared by fusion, SnTe x Se 1− x ( x = 0.68) alloy is found to possess mixed phases of hexagonal Te and orthorhombic SnSe. The deposited films of this alloy demonstrate incongruent evaporation of the constituents. Reductions in c-parameter and strain along the z -axis in lattices of SnSe and Te constituents have been observed in these films at 353 K. These deviations in the structure of SnTe x Se 1− x films make it superior to SnSe for various optoelectronic applications. The absorption coefficient of SnTe x Se 1− x films is higher than SnSe, and its bandgap attains a value of 0.93 eV. Further, resistivity value of SnTe x Se 1− x (∼ 6.12 × 10 −2 Ω cm) is lower and carrier concentration (∼ 1.31 × 10 19 cm −3 ) is higher than SnSe, whereas its mobility value (∼ 25.8 cm 2 /V s) matches SnSe and similar materials. The surface quality of SnTe x Se 1− x improves and number of crystallites increases. The interface of p -SnTe x Se 1− x with Ag metal forms a Schottky diode. The current–voltage ( I – V ) behaviour of Ag/ p -SnTe x Se 1− x Schottky diodes is analysed and diode parameters are determined by using thermionic emission and diffusion (TED) current transport mechanism.