MoS$_2$ Dual-gate Transistors with Electrostatically Doped Contacts

TL;DR

This paper introduces a novel tri-gate MoS2 transistor architecture with dual-gate and side-gate controls, enabling electrostatic doping of contacts, reduced resistance, and high-performance metrics suitable for advanced 2D-TMD electronics.

Contribution

The work presents a new tri-gate MoS2 transistor design with independently controlled gates, allowing electrostatic doping of contacts and improved device performance.

Findings

Achieved ON-OFF ratio of 3×10^7

Subthreshold swing of 83 mV/decade

Effective electrostatic doping of source/drain regions

Abstract

Two-dimensional (2D) transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2) have been intensively investigated because of their exclusive physical properties for advanced electronics and optoelectronics. In the present work, we study the MoS2 transistor based on a novel tri-gate device architecture, with dual-gate (Dual-G) in the channel and the buried side-gate (Side-G) for the source/drain regions. All gates can be independently controlled without interference. For a MoS2 sheet with a thickness of 3.6 nm, the Schottky barrier (SB) and non-overlapped channel region can be effectively tuned by electrostatically doping the source/drain regions with Side-G. Thus, the extrinsic resistance can be effectively lowered, and a boost of the ON-state current can be achieved. Meanwhile, the channel control remains efficient under the Dual-G mode, with an ON-OFF current ratio of 3E7 and subthreshold swing of 83 mV/decade. The corresponding band diagram is also discussed to illustrate the device operation mechanism. This novel device structure opens up a new way toward fabrication of high-performance devices based on 2D-TMDs.