Impact of edge roughness on the electron transport properties of MoS2 ribbons

Abstract

Edge roughness is expected to play a major role in narrow ribbons obtained from two-dimensional materials, due to the large length/surface ratio of the disordered edges with respect to the whole system surface. In the case of semiconducting transition metal dichalcogenides, a physical and quantitative understanding of the impact of edge roughness on the transport properties of ribbons with nanometer widths is essential in view of their potential applications in ultrascaled nanoelectronics. By means of atomistic quantum transport simulations, we show that the conductance due to edge states within the bulk gap is strongly suppressed by roughness. The corresponding localization length is found to be in the order of few nanometers. At low carrier energies outside the gap, edge roughness drives the system into the diffusive transport regime. The study of the mean free path, under different conditions of roughness and for different ribbon widths, shows that the conductance is moderately affected for widths above 10 nm and lengths in the order of 100 nm, with a more significant degradation for ultra-narrow ribbons.