SnTe x Se1−x Alloy: An Effective Alternative to SnSe Nano-crystalline Thin Films for Optoelectronic Applications

As prepared by fusion, SnTexSe1−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 SnTexSe1−x films make it superior to SnSe for various optoelectronic applications. The absorption coefficient of SnTexSe1−x films is higher than SnSe, and its bandgap attains a value of 0.93 eV. Further, resistivity value of SnTexSe1−x (∼ 6.12 × 10−2 Ω cm) is lower and carrier concentration (∼ 1.31 × 1019 cm−3) is higher than SnSe, whereas its mobility value (∼ 25.8 cm2/V s) matches SnSe and similar materials. The surface quality of SnTexSe1−x improves and number of crystallites increases. The interface of p-SnTexSe1−x with Ag metal forms a Schottky diode. The current–voltage (I–V) behaviour of Ag/p-SnTexSe1−x Schottky diodes is analysed and diode parameters are determined by using thermionic emission and diffusion (TED) current transport mechanism.