Gate voltage controllable device based on black phosphorus/blue phosphorus heterostructure

Abstract

As the devices approach their scaling limit, finding new material or technology for next generation nano-devices becomes one of the most important tasks in modern electronic industry. Here, based on the first principles calculations, we have systematically studied the effects of gate voltages on black phosphorus/blue phosphorus (black-P/blue-P) van der Waals heterojunction (vdWh). Our results show that the black-P/blue-P vdWh can transform from a semiconductor to a metal when the gate voltage is strong enough. In addition, the local density of states (LDOS) at the Fermi level are mainly localized either in the topmost or bottom layer depending on the gate voltage. Based on these properties, a two-gated device is proposed. By changing the directions of the applied gate voltages on electrodes, the device can realize "ON" or "OFF" states. The calculated transmission coefficient of black-P/blue-P vdWh is sensitive to the direction of two gate voltages, which can be understood based on the distribution of electrons on different atomic layers and asymmetric structure in the heterojunction. These findings may serve as a guidance for designing of novel devices with improved performance based on the 2D materials.