Effective Electrostatic Coupling of MoS2 FETs via Structural and Dielectric Engineering

Abstract

As semiconductor technology continues to scale down, the need for advanced materials and structures to enable further miniaturization and performance enhancement becomes critical. Two-dimensional (2D) semiconductors, such as MoS2, have emerged as promising candidates for next-generation electronics due to their atomic-scale thickness, high carrier mobility, and excellent electrostatic control. However, the electrostatic coupling in conventional single-gate 2D field-effect transistors (FETs) remains insufficient to achieve high performance, particularly in terms of drive current density and leakage current. Herein, we fabricate multilayer MoS2 based dual-gate field effect transistors (DG-FETs) simultaneously exhibiting greatly improved on-state current of ION = 3.9 × 10-6 A as well as low leakage current of IOFF = 1.5 × 10-15 A compared to single-gate FET. Additionally, we introduce LaOCl, a high- k van der Waals dielectric, as a gate insulator to further enhance electrostatic coupling and minimize charge trapping at the interface. When compared to conventional dielectrics (e.g. Al2O3), LaOCl-based transistors show a remarkable improvement in field-effect mobility (~28.7 cm²/V·s), the on/off ratio (~1.1 × 10¹⁰), negligible hysteresis (2.5 mV) and subthreshold swing (~96 mV/dec). These characteristics demonstrate the potential of multi-gate and dielectric engineering to achieve high- performance 2D semiconductors, paving the way for future low-power, high-speed electronic applications.