Large current modulation in exfoliated-graphene/MoS2/metal vertical heterostructures

TL;DR

This paper demonstrates a graphene/MoS2/metal vertical heterostructure that achieves high current modulation and density, showing promise for high-speed switching devices by leveraging gate-controlled Schottky barriers.

Contribution

The study introduces a mechanically exfoliated graphene/MoS2/metal heterostructure with a gate-tunable Schottky barrier, enabling large current modulation and high current density in vertical transistors.

Findings

Current modulation exceeds 10^5 times.

Achieves a current density of ~10^4 A/cm^2.

Demonstrates high-performance vertical FET operation.

Abstract

Graphene-based vertical field effect transistors have attracted considerable attention in the light of realizing high-speed switching devices; however, the functionality of such devices has been limited by either their small ON-OFF current ratios or ON current densities. We fabricate a graphene/MoS2/metal vertical heterostructure by using mechanical exfoliation and dry transfer of graphene and MoS2 layers. The van der Waals interface between graphene and MoS2 exhibits a Schottky barrier, thus enabling the possibility of well-defined current rectification. The height of the Schottky barrier can be strongly modulated by an external gate electric field owing to the small density of states of graphene. We obtain large current modulation exceeding 10^5 simultaneously with a large current density of ~10^4 A/cm^2 , thereby demonstrating the superior performance of the exfoliated-graphene/MoS2/metal vertical field effect transistor