Recent Progress of Novel Thermoelectric SnSe Semiconductor Crystal

SnSe crystal is novel Ⅳ-Ⅵ group compound semiconductor thermoelectric material, it has very low intrinsic thermal conductivity and ultra-high figure of merit ZT value. Due to its high performance, environmental friendly and low cost advantages, the research of SnSe crystal has become a hot point around the world. However, the growth of large size SnSe crystal is hard mainly because of its layer crystal structure and complicated thermal expansion behavior. In this paper, some growth methods for SnSe crystal growth are introduced and compared, such as horizontal vapour method, vertical Bridgman method and vertical gradient frozen method. Additionally, the growth result of SnSe by a horizontal Bridgman method in our group is also reported which is concluded would be a key technology for high quality and large size SnSe crystal growth in the future. Moreover, the figure of merit ZT of different SnSe crystals is also compared, and its value variation is analyzed. This review paper would be helpful for deep understanding the growth character of SnSe crystal, and it will provide suggestions for SnSe crystal fabrication and property investigation in future.