Influence of sulphur doping in snse nanoflakes prepared by microwave assisted solvothermal synthesis

Nanostructured SnSe studied for their high Seebeck coefficient with low thermal conductivity is reported to be a potential material for thermoelectric applications. Recently, nano-structuring of SnSe withsulphurdoping has been estimated theoretically to enhance the figure of merit and hence ispredicted to be favourable for thermoelectric applications. Thestructural, optical and morphological properties of SnSe nanoflakessynthesized via scalable and facile microwave assisted solvothermal synthesis isreported in this work. X-ray diffraction reveals a single phase orthorhombic structure with a crystallite size of ∼38nm. Morphology studies from FESEM reveals that the edge to edge length of single flake is ∼1.3 µm. Topography studies from AFM indicate square-like two dimensional nanoflakeswith length of 1.6 µm,breadth of 800nm, thickness of ∼250nmand roughness 36rms. Optical properties indicate a direct band gap of ∼1.03eV. Energy dispersive spectroscopy (EDS) demonstrates the presence of 9% sulphur along with the expected 1:1 ratio of Sn and Se that is attributed to the presence of monolayer of Thioglycolic acid (TGA) which is used as the shape directing agent. A fine tuning of morphology as well as optimization of sulphur content is possible by TGA which would be promising for thermoelectric application.