Nano-crystalline tin selenide thin films: synthesis and characterization

Abstract

A simple, straightforward, and facile drop-casting technique was used to prepare thin films of tin selenide (SnSe) at 220 °C substrate temperature using triethanolamine as complexing agent. SnCl2 and Na2SeSO3 precursors were used as source materials for the thin film synthesis. The drop-casted film was annealed at 400 °C. Surface morphological, structural, electrical, and optical properties of the synthesized films were analyzed by scanning electron microscope (SEM), energy dispersive X-ray analysis (EDAX), X-ray powder diffraction (XRD), high-precision digital multimeter, and UV–visible spectroscopy, respectively. The XRD study of synthesized film showed the presence of nanocrystallinity with orthorhombic crystal structure of SnSe. SEM images indicated that small grains agglomerated to form a bunch of bigger size. SEM data showed good continuity of SnSe film. Hot probe method was used to confirm the carrier type of film. SnSe thin films were p-type having 1.4 eV bandgap, and their electrical conductivity was in the order of 10 S cm−1 which made them suitable to use it in the solar cell as an absorber layer.