Field-effect transistors of high-mobility few-layer SnSe2

We report the transport properties of mechanically exfoliated few-layer SnSe2 flakes, whosemobility is found to be ∼85 cm2 V−1 s−1 at 300  K, higher than those of the majority of few-layer transitional metal dichalcogenides. Themobility increases strongly with decreasedtemperature, indicating aphonon limited transport. The conductivity of the semiconducting SnSe2 shows a metallic behavior, which is explained by two competing factors involving the differenttemperature dependence ofmobility andcarrier density. TheFermi level is found to be 87  meV below the conduction band minima (CBM) at 300 K and 12 meV below the CBM at 78 K, resulting from a heavy n-typedoping. Previous studies have found SnSe2field-effect transistors to be very difficult to turn off. We find the limiting factor to be the flake thickness compared with the maximum depletion width. With fully depleted devices, we are able to achieve a current on-off ratio of ∼105. These results demonstrate the great potential of SnSe2 as a two dimensional (2D) semiconductingmaterial and are helpful for our understanding of other heavilydoped 2Dmaterials.

Source: Applied Physics Letters - November 14, 2016 Category: Physics Authors: Chenglei Guo, Zhen Tian, Yanjun Xiao, Qixi Mi and Jiamin Xue Source Type: research