SiO2基底Nb原位掺杂MoS2纳米薄膜的制备及场效应

Preparation and Field-effect Mobility of Nb Doped MoS2 Nano-films on SiO2 Substrate

以氧化钼(MoO3)、硫(S)和氯化铌(NbCl5)作为前驱体,利用一锅两步化学气相沉积法,在SiO2基底上大面积地生长连续性好、均匀负载的Nb-MoS2薄膜结构。通过扫描电子显微镜(SEM)和原子力显微镜(AFM)表征可知薄层具有较好的连续性,同时使用拉曼光谱(Raman)、光致发光光谱(PL)和X射线光电子能谱(XPS)证实了掺杂后薄膜内部出现高达90meV的蓝移现象。将薄膜制成场效应管(FET),并对其电学性能进行测试得出,场效应迁移率为1.22cm^2·V^-1·s^-1,电流开关比为10^5,并证实了当Nb掺杂入MoS2薄膜后使得薄膜整体阻抗大幅降低,整体阻抗降低到66.67kΩ,比未掺杂Nb的MoS2薄膜降低了约40%。本工艺操作简单、成本低、重现率高,为制备高质量、大面积过渡金属掺杂的MoS2薄膜光电学器件提供了新的途径。

In this study, large-area growth of Nb-MoS2 layers on SiO2 substrates using one-pot chemical vapor deposition via two steps was successfully achieved. For the first time, a facile, cost-effective and mass-scalable direct synthesis approach was designed for doping Nb into MoS2 layers using MoO3, sulfur (S) and NbCl 5 as precursors. The proposed process allowed retaining the uniformity of large area thin layers which are sui-table for device fabrication. The structural and optical properties of the resulting Nb-MoS2 layers were systematically investigated. Scanning electron microscope (SEM), atomic force microscope (AFM), Raman, photoluminescence (PL) spectra and X-ray photoelectron spectroscopy (XPS) analyses confirmed the formation of continuous and crystalline few-layers MoS2 and Nb-MoS2. An obvious blue-shift of up to 90 meV in photoluminescence peaks was observed for samples with different grain sizes. The electrical properties of the as-prepared materials were evaluated by bottom-gate FETs. A field-effect mobility of 1.22 cm^2·V^-1 ·s^-1 and a current on/off ratio of 10^5 were obtained. In particular, Nb-MoS2 prepared by Nb doping greatly reduced the resistance of the film to 66.67 kΩ. These findings provide a novel route towards scaled-up synthesis of high-quality few-layered MoS 2 by transition-metal doping in TMDCs which are suitable for electronic and optoelectronic devices.