Probing effects of disorders in few-layer ReS₂ via electron transport.

Structural anisotropy in Rhenium disulfide (ReS2) leads to intriguing optical and electronic properties which is promising for polarization-controlled optoelectronic devices. However, the fabrication of devices with good electrical contacts and electron mobility in ReS₂ can be challenging. Here we report the electronic transport properties of a graphene-contacted few-layer ReS₂ field effect transistor fabricated using the dry transfer technique in top-gated geometry. We observed a mobility value of ~ 5 cm^2/V-s at room temperature which can be considered as the highest mobility reported so far in ReS₂ FETs, thus showing the pristine quality of the ReS₂ channel. Furthermore, we investigated the effect of unintentional defects in the exfoliated ReS2 layers via the temperature-dependent electron transport down to 3.2 K and we find that at high temperatures the nearest neighbour hopping dominates the transport mechanism, whereas the 2D variable range hopping takes place at low to moderate temperatures. We report the localization length to be ̴ 200 nm at a fixed top-gate voltage of 5 V. Our study reveals the effect of the defects of ReS₂ on the electrical transport which will be useful in improving the device performance.