High-Performance p-Type Field-Effect Transistor Based on WS2 Monolayer Prepared by Liquid-Phase-Assisted Space-Confined CVD

Although some progress has been made in the synthesis of p-type two-dimensional (2D) WS2, the hole mobility of WS2 field-effect transistors (FETs) is still very low, significantly impeding its application in logic complementary circuits. In this study, p-type 2D WS2 has been successfully prepared by liquid-phase assisted space-confined chemical vapor deposition (LASCVD) method and machine learning (ML) has been employed to optimize the process parameters of the growth of WS2 nanosheets. Results show that, under the optimal growth conditions, the maximum domain size of WS2 monolayer reaches 475 μm. Additionally, W vacancies in WS2 nanosheets have been observed through STEM-HAADF, Raman and PL analysis, contributing to the p-type characteristic of 2D WS2. Moreover, p-type high-performance FETs based on the WS2 monolayer have been fabricated, exhibiting a high hole mobility of 46.87 cm2 V–1 s–1 and an on/off ratio of 105. This study provides a promising direct synthesis method for p-type 2D TMDCs.