Large bandgap and a high carrier mobility in few-layer arsenene

We demonstrate few-layer arsenene similar to black phosphorene, derived from the orthorhombic bulk arsenic, is thermally stable, semiconducting and of high carrier mobility. The monolayer is an indirect bandgap semiconductor. Once any more layer is added, multilayer arsenenes always behave as direct bandgap semiconductors with gap value in the order of 1 eV. The indirect-direct bandgap transformation is demonstrated to be dictated by a mutual competition between the two intralayer bondings. Based on the so-called acoustic phonon limited approach, the carrier mobility of few-layer arsenene is theoretically predicted. The results show that a large directional anisotropy of transport and a high intrinsic carrier mobility of several thousand square centimeters per voltsecond coexist in few-layer arsenene. All these make few-layer arsenene intriguing for future devices applications in semiconducting industry.