A comparative computational study of tunneling transistors based on vertical graphene–hBCN heterostructures

Abstract

In this paper, the electrical characteristics of tunneling transistors based on vertical graphene and a hexagonal boron-carbon-nitrogen (hBCN) heterostructure are studied and compared theoretically. We have considered three different types of hBCN, i.e., BC2N, BC2N′, and BC6N as a tunneling barrier. Our simulation is based on the nonequilibrium Green’s function formalism along with an atomistic tight-binding (TB) model. The TB parameters are obtained by fitting the band structure to first-principles results. By using this method, electrical characteristics of the device, such as the ION/IOFF ratio, subthreshold swing, and intrinsic gate-delay time, are investigated. For a fair comparison, the effects of geometrical variations and number of tunneling barrier layers on the electrical parameters of the device are simulated and investigated. We show that, by an appropriate design, the device can be used for low-power or high-performance applications. The device allows current modulation exceeding 106 at room temperature for a 0.6 V bias voltage.