Fowler-Nordheim tunneling characteristics of graphene/hBN/metal heterojunctions

The heterostructures of low-dimensional materials are considered promising candidates for future electronic devices. In this work, we manifest the interlayer hexagonal boron nitride (hBN) thickness dependent tunneling characteristics of graphene/hBN/metal heterojunction back-gated field effect transistors (FETs). Direct tunneling of charge carriers through the ultrathin hBN layer is noticed at low bias voltages. Besides, Fowler-Nordheim tunneling takes place at high bias voltages revealing an increase in the barrier height with an interlayer film thickness. In addition, the back-gate dependent tunneling properties of graphene/hBN/metal heterojunction back-gated FETs are investigated. Furthermore, the Fermi level of graphene is tuned via back-gate voltages that results in the modification of the tunneling current, threshold voltage, and barrier height of the device. This could be an effective approach to modify the tunneling features of vertical heterostructures for their prospective role in next generation high performance electronic devices.