Improvement of P-Type Contact in WSe₂ Field-Effect Transistors via Defect Engineering.

Abstract

Two-dimensional (2D) material-based p-channel field-effect transistors (FETs) are key elements for the realization of complementary metal-oxide-semiconductor (CMOS) technology. WSe₂, as the primary material for p-channel FETs, is suffering from intrinsic atomic defects and extrinsic defects during metal deposition, making it difficult to form high-quality metal-semiconductor contact interfaces. This leaves significant space for improvement in the performance of p-channel FETs. In this work, we propose an effective defect optimization strategy, focusing on the contact interface. The trifluoromethyl thianthrenium triflate (TTT) molecule treatment on WSe₂ increases the hole density, induces the defect passivation, and enhances the hole transport efficiency. The high work-function semimetal TiS₂ effectively prevents damage caused by metal deposition and facilitates efficient hole transport. The optimized WSe₂-CF₃-TiS₂ FET achieves a high hole mobility of ∼147 cm²/V·s and demonstrates excellent stability at 200 °C.