Tang Lei, Li Tao, Luo Yuting, Feng Simin, Cai Zhengyang, Zhang Hang, Liu Bilu, Cheng Hui-Ming
Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, Guangdong 518055, P. R. China.
Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, P. R. China.
ACS Nano. 2020 Apr 28;14(4):4646-4653. doi: 10.1021/acsnano.0c00296. Epub 2020 Apr 17.
Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted great attention due to their physical and chemical properties that make them promising in electronics and optoelectronics. Because of the difficulties in controlling concentrations of solid precursors and spatially nonuniform growth dynamics, it is challenging to grow 2D TMDCs over large areas with good uniformity and reproducibility so far, which significantly hinders their practical use. Here we report a vertical chemical vapor deposition (VCVD) design with gaseous precursors to grow monolayer TMDCs with a uniform density and high quality over the whole substrate and with excellent reproducibility. Such a gaseous VCVD design can well control the three key parameters in TMDC growth, including precursor concentration, gas flow, and temperature, which cannot be done in a currently widely used horizontal CVD system with solid precursors. Statistical results show that VCVD-grown monolayer TMDCs including MoS and WS are of high uniformity and quality on substrates over centimeter size. We also fabricated multiple van der Waals heterostructures by one-step transfer of VCVD-grown TMDCs, owning to their good uniformity. This work sheds light on the growth of 2D materials with high uniformity on a large-area substrate, which can be used for the wafer-scale fabrication of 2D materials and their heterostructures.
二维（2D）过渡金属二硫属化物（TMDCs）因其物理和化学性质在电子学和光电子学领域具有广阔应用前景而备受关注。由于难以控制固体前驱体的浓度以及空间上不均匀的生长动力学，迄今为止，在大面积上以良好的均匀性和可重复性生长二维TMDCs具有挑战性，这严重阻碍了它们的实际应用。在此，我们报告一种采用气态前驱体的垂直化学气相沉积（VCVD）设计，可在整个衬底上以均匀的密度和高质量生长单层TMDCs，且具有出色的可重复性。这种气态VCVD设计能够很好地控制TMDC生长中的三个关键参数，包括前驱体浓度、气流和温度，而这在目前广泛使用的采用固体前驱体的水平CVD系统中是无法实现的。统计结果表明，通过VCVD生长的包括MoS和WS在内的单层TMDCs在厘米尺寸的衬底上具有高度的均匀性和质量。由于其良好的均匀性，我们还通过一步转移VCVD生长的TMDCs制备了多个范德华异质结构。这项工作为在大面积衬底上以高均匀性生长二维材料提供了思路，可用于二维材料及其异质结构的晶圆级制造。
