First-principles investigations on MXene-blue phosphorene and MXene-MoS2 transistors

In the semiconductor industry, one of the most important steps in the development of electronic devices is the discovery of electrode materials that are suitable for ohmic contact. As a newly found type of 2D materials, MXenes have been explored as materials for use in field effect transistors (FETs) with promising performances, which urges for the underlying mechanisms to be understood. In this work, the behaviors of the 5–10 nm device models for monolayer blue phosphorene (BlueP) and MoS2 with a MXene electrode are investigated using ab initio quantum transport simulations. Firstly, the interfacial properties of BlueP and MoS2 in contact with M3C2T2 (M = Ti, Zr, or Hf; T = F, OH, or O) MXene are studied. The results show that OH and some of the F functionalized MXenes form an n-type ohmic contact with BlueP or MoS2, while the O functionalized MXenes form a p-type ohmic contact with BlueP and MoS2. Accordingly, when the FET model is built with M3C2(OH)2 electrodes, these FETs exhibit high on-currents due to the ohmic contacts with subthreshold swing between 100 ∼ 200 mV/decade, and high on/off ratios up to 106 at a bias voltage of 0.5 V. Our results imply that a FET with a sub-10 nm channel length can satisfy the requirements of both high performance and low power logic applications. The results from this study indicate that MXenes may act as the appropriate electrode for high-performance BlueP and MoS2 FETs, which may provide new clues to guide the application of various 2D materials in electronics.