First-Principles Study on the Modulation of Schottky Barrier in Graphene/Janus MoSSe Heterojunctions by Interface Contact and Electric Field Effects

TL;DR

This paper explores how the Schottky barrier in graphene/Janus MoSSe heterojunctions can be modulated by interface contact and electric fields, enabling control over electronic properties for nanoelectronics.

Contribution

The study reveals how interface contact and electric fields can switch the Schottky barrier type and transition to Ohmic contact in Gr/JMoSSe heterojunctions.

Findings

Contact with S atoms forms an n-type Schottky barrier, while contact with Se atoms forms a p-type Schottky barrier.

Increasing JMoSSe layers can transition the contact from Schottky to Ohmic.

An external electric field enables transitions among n-type, p-type, and Ohmic contacts.

Abstract

Constructing heterojunctions can combine the superior performance of different two-dimensional (2D) materials and eliminate the drawbacks of a single material, and modulating heterojunctions can enhance the capability and extend the application field. Here, we investigate the physical properties of the heterojunctions formed by the contact of different atom planes of Janus MoSSe (JMoSSe) and graphene (Gr), and regulate the Schottky barrier of the Gr/JMoSSe heterojunction by the number of layers and the electric field. Due to the difference in atomic electronegativity and surface work function (WF), the Gr/JSMoSe heterojunction formed by the contact of S atoms with Gr exhibits an n-type Schottky barrier, whereas the Gr/JSeMoS heterojunction formed by the contact of the Se atoms with Gr reveals a p-type Schottky barrier. Increasing the number of layers of JMoSSe allows the Gr/JMoSSe heterojunction to achieve the transition from Schottky contact to Ohmic contact. Moreover, under the control of an external electric field, the Gr/JMoSSe heterojunction can realize the transition among n-type Schottky barrier, p-type Schottky barrier, and Ohmic contact. The physical mechanism of the layer number and electric field modulation effect is analyzed in detail by the change in the interface electron charge transfer. Our results will contribute to the design and application of nanoelectronics and optoelectronic devices based on Gr/JMoSSe heterojunctions in the future.

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