Growth of SnSe single crystal via vertical vapor deposition method and characterization of its thermoelectric performance

Abstract

In this work, a vertical vapor deposition method was developed to grow SnSe single crystals. More than thirty single crystal particles were simultaneously obtained and the largest size could up to 15 × 15 × 10 mm3. The as-grown crystal is tested has nearly Sn: Se = 1: 1 stoichiometric ratio and demonstrates standard orthorhombic Pnma space group at room temperature. Electrical transport measurement shows the present SnSe single crystal has a largest electrical conductivity σ = 39.6 S cm−1 near Pnma- Cmcm phase transition temperature, and the maximum Seebeck coefficient S = 566 μVK-1 is taken place around 580 K. Thermal transport analysis implies SnSe single crystal exhibits a lowest total thermal conductivity ktot=0.44 Wm−1 K−1 near Pnma- Cmcm phase transition. Finally, it is calculated the figure of merit ZT has a largest value ∼1.0 around 800 K that implies SnSe single crystal is a promising middle- temperature TE material.