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

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.