Wang Siyuan, Wang Pinyi, Tang Hailun, Yu Shilong, Ye Huihui, Fang Xinyu, Ding Jing, Yang Yang, Li Hai
School of Flexible Electronics (Future Technologies), Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China.
Nanomaterials (Basel). 2024 Dec 16;14(24):2021. doi: 10.3390/nano14242021.
Two-dimensional WSe nanosheets have received increasing attention due to their excellent optoelectronic properties. Solid precursors, such as WO and Se powders, have been extensively employed to grow WSe nanosheets by the chemical vapor deposition (CVD) method. However, the high melting point of WO results in heterogeneous nucleation sites and nonuniform growth of the WSe nanosheet. By dissolving WO powder in a NaOH solution, we report a facile and uniform growth of monolayer and bilayer WSe nanosheets on a SiO/Si substrate at a large scale using liquid precursor by the CVD method. The size and thickness of the WSe nanosheets were controlled by modulating the precursor concentration and growth temperature. The as-prepared monolayer and bilayer WSe nanosheets were well characterized by optical microscopy, atomic force microscopy, and Raman and photoluminescence spectroscopy. With the increase in precursor concentration, the size of the monolayer WSe increased up to 120 μm. Bilayer WSe nanosheets were grown at higher temperatures. The photosensitivity of the bilayer WSe was one order of magnitude higher than that of the monolayer WSe. The carrier mobility, specific detectivity, photoresponsivity, and external quantum efficiency of the bilayer WSe were about two orders of magnitude higher than those of the monolayer WSe. Our method opens up a new avenue to grow monolayer and bilayer WSe for optoelectronic applications.
二维WSe纳米片因其优异的光电性能而受到越来越多的关注。固体前驱体，如WO和Se粉末，已被广泛用于通过化学气相沉积（CVD）法生长WSe纳米片。然而，WO的高熔点导致了WSe纳米片的异质成核位点和不均匀生长。通过将WO粉末溶解在NaOH溶液中，我们报道了一种使用液体前驱体通过CVD法在SiO/Si衬底上大规模轻松且均匀地生长单层和双层WSe纳米片的方法。通过调节前驱体浓度和生长温度来控制WSe纳米片的尺寸和厚度。所制备的单层和双层WSe纳米片通过光学显微镜、原子力显微镜以及拉曼光谱和光致发光光谱进行了很好的表征。随着前驱体浓度的增加，单层WSe的尺寸增大至120μm。双层WSe纳米片在更高温度下生长。双层WSe的光敏性比单层WSe高一个数量级。双层WSe的载流子迁移率、比探测率、光响应度和外量子效率比单层WSe高约两个数量级。我们的方法为用于光电子应用的单层和双层WSe的生长开辟了一条新途径。
