Electron-Transport Properties of Few-Layer Black Phosphorus.

We perform the first-principles computational study of the effect of number of stacking layers and stacking style of the few-layer black phosphorus (BPs) on the electronic properties, including transport gap, current-voltage (i-v) relation, and differential conductance. Our computation is based on the nonequilibrium Green's function approach combined with density functional theory calculations. Specifically, we compute electron-transport properties of monolayer BP, bilayer BP, and trilayer BP as well as bilayer BPs with AB-, AA-, or AC-stacking. We find that the stacking number has greater influence on the transport gap than the stacking type. Conversely, the stacking type has greater influence on i-v curve and differential conductance than on the transport gap. This study offers useful guidance for determining the number of stacking layers and the stacking style of few-layer BP sheets in future experimental measurements and for potential applications in nanoelectronic devices.