Anisotropic Electron transport and device applications of atomically thin ReS$_{\mathrm{2}}$

Semiconducting two-dimensional transition metal dichalcogenides are emerging as top candidates for post-silicon electronics. While most of them exhibit isotropic behavior, lowering the lattice symmetry could induce anisotropic properties, which are both scientifically interesting and potentially useful. In this talk, we will present atomically thin rhenium disulfide (ReS$_{\mathrm{2}})$ flakes with unique distorted 1T structure, which exhibit in-plane anisotropic properties. We first fabricated mono- and few-layer ReS$_{\mathrm{2}}$ field effect transistors, which exhibit competitive performance with large current on/off ratios (\textasciitilde 10$^{\mathrm{7}})$ and low subthreshold swings (100 mV dec$^{\mathrm{-1}})$. The observed anisotropic ratio along two principle axes reaches up to 3.1. Furthermore, we successfully demonstrated an integrated digital inverter with good performance by utilizing two ReS$_{\mathrm{2}}$ anisotropic field effect transistors, suggesting the promising implementation of large-scale two-dimensional logic circuits. Recent results on ultra-high responsivity (as high as 88,600 A W$^{\mathrm{-1}})$ phototransistors based on few-layer ReS$_{\mathrm{2}}$ will also be discussed. Our results underscore the unique properties of two-dimensional semiconducting materials with low crystal symmetry for future electronic and optoelectronic applications.