Anisotropic electron transport behaviors in few-layer ReSe2*

The transition metal dichalcogenide of ReSe2 had drawn much attention for decades since it is a layered semiconductor with strong anisotropy on the basal plane. The Re atoms are arranged to form clusters with the clusters aligned in a specified ‘b’-axis. After the improvement of material science, the anisotropy on the basal plane can be studied on single layer ReSe2. In this talk, we will discuss the electrical exploration of the anisotropy on the basal plane of ReSe2. We applied the mechanical exfoliation to make few-layer ReSe2 flakes and the standard electron-beam lithography to make circularly oriented probing electrodes on the basal plane. We checked that the contact resistance is very small as compared with the ReSe2 channel resistance. Using the circularly arranged electrodes, we studied electron transport in the direction parallel to the b-axis and in the direction making an angle with the b-axis. We studied angle dependence of electron mobility, the disorder parameter T0 of the Mott’s variable range hopping model, the metal-insulator transition, and the thermoelectric power. We observe an enhanced conductivity in the b-axis on the basal plane of the ReSe2.