Unexpected Electron Transport Suppression in a Heterostructured Graphene-MoS2 Multiple Field-Effect Transistor Architecture.

Gaia Ciampalini,Guido Menichetti,Alessandro Pitanti,Stefano Roddaro,Luca Buoni,Simona Pace,Camilla Coletti,Vaidotas Mišeikis,Dario Pisignano,Alessandro Tredicucci,Filippo Fabbri

doi:10.1021/acsnano.1c09131

Abstract

We demonstrate a graphene–MoS2 architecture integrating multiple field-effect transistors (FETs), and we independently probe and correlate the conducting properties of van der Waals coupled graphene–MoS2 contacts with those of the MoS2 channels. Devices are fabricated starting from high-quality single-crystal monolayers grown by chemical vapor deposition. The heterojunction was investigated by scanning Raman and photoluminescence spectroscopies. Moreover, transconductance curves of MoS2 are compared with the current–voltage characteristics of graphene contact stripes, revealing a significant suppression of transport on the n-side of the transconductance curve. On the basis of ab initio modeling, the effect is understood in terms of trapping by sulfur vacancies, which counterintuitively depends on the field effect, even though the graphene contact layer is positioned between the backgate and the MoS2 channel.

Highlights

We demonstrate a graphene−MoS2 architecture integrating multiple field-effect transistors (FETs), and we independently probe and correlate the conducting properties of van der Waals coupled graphene−MoS2 contacts with those of the MoS2 channels
Article of van der Waals (vdW) interfaces leads to changes in the transport properties of the individual materials involved in field-effect transistor (FET) devices is still missing
Each stripe can act as ohmic contact for a MoS2 backgated FET and be simultaneously contacted at its terminations to implement an additional MoS2-covered graphene FET. This structure can so act as a MoS2 FET and as a set of graphene FETs at the same time, which will be referred to as a multi-FET in the following

Summary

Introduction

We demonstrate a graphene−MoS2 architecture integrating multiple field-effect transistors (FETs), and we independently probe and correlate the conducting properties of van der Waals coupled graphene−MoS2 contacts with those of the MoS2 channels. F ormed when two or more atomically thin crystals are bonded by van der Waals (vdW) interaction,[1] vdW heterostructures are intriguing architectures, enabled by the discovery of two-dimensional (2D) materials, such as graphene, hexagonal boron nitride, and transition metal dichalcogenides (TMDs). Within this family, peculiar junctions can be obtained when graphene is used as a contact material for a TMD monolayer. Article of vdW interfaces leads to changes in the transport properties of the individual materials involved in field-effect transistor (FET) devices is still missing

Methods

Results

Conclusion