Controlling Tunneling Characteristics via Bias Voltage in Bilayer Graphene/WS/Metal Heterojunctions.

Van der Waals heterojunctions, formed by stacking two-dimensional materials with various structural and electronic properties, opens a new way to design new functional devices for future applications and provides an ideal research platform for exploring novel physical phenomena. In this work, bilayer graphene/WS/metal heterojunctions (GWMHs) with vertical architecture were designed and fabricated. The tunneling current-bias voltage ( - ) properties of GWMHs can be tuned by 5 × 10 times in magnitude for current increasing from 0.2 nA to 1 mA with applied bias voltage increasing from 10 mV to 2 V. Moreover, the transfer properties of GWMHs exhibit n-type conduction at = 0.1 V and bipolar conduction at = 2 V; these findings are explained well by direct tunneling () and Fowler-Nordheim tunneling (), respectively. The results show the great potential of GWMHs for high-power field-effect transistors (FETs) and next-generation logic electronic devices.