Tunable Vanadium Doping of Bilayer MoS₂ by Co-Sputtering System for Electronic Applications

Zih-Siang Jian^1,2*, Jie-Ru Yen¹, Huai-En Zeng¹, Wen-Hao Chang^1,2,3

¹Department of Electrophysics, National Yang Ming Chiao Tung University, HsinChu, Taiwan
²Research Center for Critical Issues, Academia South Sinica, Tainan, Taiwan
³Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan

* Presenter:Zih-Siang Jian, email:darke047.sc10@nycu.edu.tw

Molybdenum disulfide (MoS₂) is gaining attention for its unique properties, such as nonzero-gap property and good electrical conductivity. However, developing reliable circuits using MoS₂ still faces challenges, including a lack of precise control over carrier concentration, conductivity, threshold voltages, and high contact resistance. Developing an efficient strategy for doping the 2D materials is required for the state-of-the-art technology. Thus, Co-sputtering of 2D materials and dopant followed by post-growth sulfurization is considered as a feasible approach to control doping concentration of MoS₂. In this work, we demonstrate a controllable doping in MoS₂ by co-sputtering 2D materials and dopant on single-crystal MoS₂ templates followed by post-growth sulfurization. We co-sputtered vanadium (V) with MoS₂ onto a single-crystal MoS₂ film for the p-type doping. Post-growth annealing in H₂S was performed for healing the crystallinity after the co-sputtering. By controlling the sputtering parameters of dopants and MoS₂, tunable p-type doping concentrations were achieved. Evidences of the V-doped MoS₂ film was examined using Raman spectroscopy, photoluminescence (PL) spectroscopy, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), and scanning transmission electron microscopy (STEM). We successfully achieved degenerate p-type doping in the doped MoS₂ field-effect transistors (FETs), indicating a significant enhancement in conductivity. This work provides a potential approach for doping MoS₂, highlighting its promise for future electronic applications.

Keywords: TMDs, Molybdenum disulfide, Doping, Magnetron Co-sputtering, LPCVD