Schottky Barrier Diode Characteristics of Graphene-GaN Heterojunction with Hexagonal Boron Nitride Interfacial Layer

Abstract

Metal-insulator-semiconductor (MIS) based Schottky barrier diode (SBD) has significant importance for optoelectronics and other device applications. Here, we demonstrate the fabrication of a highly rectifying Schottky barrier diode (SBD) using a thin hexagonal boron nitride (hBN) interfacial layer in graphene and n-type gallium nitride (n-GaN) heterojunction. Significant reduction of reverse saturation current is obtained with the introduction of hBN layer in graphene/n-GaN interface. The MIS based SBD shows excellent ultraviolet (UV) photoresponsivity with a light/dark ratio of ≈105 at a low reverse bias voltage (−1.5V). Temperature dependent current density-voltage (J–V) characteristics of the graphene/hBN/n-GaN heterojunction is investigated to elucidate the current transport behavior. The Schottky barrier height increased with increase in temperature from 0.77 to 0.98 eV in the temperature range of 298–373 K, respectively. The series resistance (RS) is also found to be temperature dependent, where RS decreased with increase in temperature. The understanding of graphene/hBN/n-GaN heterojunction device characteristics can be significant for photodiode and switching device applications.