Mechanical Property Of Snse Single Crystal Prepared Via Vertical Bridgman Method

IV-VI SnSe single crystal is an attractive thermoelectric (TE) material due to its outstanding TE behavior and environment friendly charactistic. In this work, an effective way for SnSe single crystal growth was explored, and the mechanical property of the as-prepared product was investigated. Undoped SnSe single crystal with accurate stoichiometric ratio was successfully grown via a vertical Bridgman method. The as-grown SnSe single crystal has standard orthorhombic Pnma space group at room temperature. It is easy to cleave along (100) plane because of its weak link between adjacent Sn-Se layers. Microindentation test reveals that SnSe single crystal is a very soft material as its average Vickers microhardness HV is only 53 MPa under 0.01-0.05 kg applied loads. However, it displays excellent fracture toughness due to strong heteropolar bonds between Sn and Se atoms inside (100) plane. The friction coefficient COF on (100) is increased from 0.09 to 0.8 as the scratch load is added from 5 to 300 mN. This work is of great significance to provide the mechanical property of SnSe single crystal.