A facile route to a high-quality graphene/MoS2 vertical field-effect transistor with gate-modulated photocurrent response

Abstract

Two-dimensional layered materials, such as graphene (Gr) and molybdenum disulfide (MoS₂), have become fascinating and exciting candidates for next-generation electronic device materials. Their vertical combinations have led to novel electronic and photonic devices. We fabricated vertical field-effect transistors (FETs) with h-BN/Gr/MoS₂/Mo multi-heterostructures. A facile route was followed to design high-quality vertical FETs with improved performance. MoS₂ was directly transferred to SiO₂/h-BN/Gr without using any polymer, which produced a clean interface between Gr and MoS₂. A high current ON–OFF ratio of ∼10⁶ was demonstrated with a high current density of ∼10⁵ A cm⁻². Our results were attributed to the high-quality bottom Gr on h-BN, the top-most molybdenum metal contact, and the clean interface between Gr and MoS₂. The photoresponse of vertical FETs was also investigated under deep ultraviolet irradiation. The current density and photocurrent response of these vertical devices were strongly dependent on the back-gate voltage.