A Two-Dimensional NiS/MoS<sub>2</sub> Metal–Semiconductor Vertical Heterojunction for a Sub-100 nm Transistor
Rui‐Hua Xu, Luying Song, Xiaohui Li, Du Zhu, Chuxuan Xiao, Hang Sun, Yanan Peng, Ling Huang, Yulin Jiang, Yinuo Li, Yuhang Li, Jun He, Jianping Shi
Abstract
The reliable contact between two-dimensional (2D) semiconducting transition-metal dichalcogenides (TMDCs) and electrodes is the prerequisite for constructing next-generation electronic devices. Despite considerable efforts having been devoted, realizing such a desirable target remains a great challenge due to the complexity of selective doping on 2D semiconducting TMDCs and the physical damage during the metal electrode integration process. Here, we propose a two-step chemical vapor deposition strategy to synthesize 2D metallic NiS with excellent electronic conductivity and robust environmental stability on monolayer MoS 2 . The in situ fabricated 2D NiS/MoS 2 vertical heterojunctions possess perfect contacts and intrinsic interfaces, which deliver distinguished device performances featured with a high average carrier mobility (59.8 cm 2 V –1 s –1 ) and large on/off current ratio. Particularly, due to the improved interface contact, monolayer MoS 2 short-channel transistors exhibit an approximate current saturation under a low drain-source bias (0.9 V) with the on-state current density of 1.20 mA μm –1, which outperforms the equivalent silicon complementary metal-oxide semiconductor and satisfies the target of the International Roadmap for Devices and Systems. This work contributes to the growth of van der Waals metal–semiconductor heterojunctions and the integration of future 2D electronics.