Engineering Research Center of IoT Technology Applications (Ministry of Education), Department of Electronic Engineering, Jiangnan University, Wuxi 214122, People's Republic of China. School of Science, Jiangnan University, Wuxi 214122, People's Republic of China.
Nanotechnology. 2018 Nov 9;29(45):455707. doi: 10.1088/1361-6528/aaddc5. Epub 2018 Aug 30.
Heterostructures of two-dimensional (2D) transition metal dichalcogenides (TMDs) offer attractive prospects for practical applications by combining unique physical properties that are distinct from those of traditional structures. In this paper, we demonstrate a three-stage chemical vapor deposition method for the growth of bilayer MoS-WS/WS heterostructures with the bottom layers being the lateral MoS-center/WS-edge monolayer heterostructures and the top layers being the WS monolayers. The alternative growth of lateral and vertical heterostructures can be realized by adjusting both the temperature and the carrier gas flow direction. The combined effect of both reverse gas flow and higher growing temperature can promote the epitaxial growth of second layer on the activated nucleation centers of the first monolayer heterostructures. By using customized temperature profiles, single heterostructures including monolayer lateral MoS-WS heterostructures and bilayer lateral WS(2L)-MoS(2L) heterostructures could also be obtained. Atomic force microscopy, photoluminescence and Raman mapping studies clearly reveal that these different heterostructure samples are highly uniform. These results thus provide a promising and efficient method for the synthesis of complex heterostructures based on different TMDs materials, which would greatly expand the heterostructure family and broaden their applications.
二维（2D）过渡金属二硫属化物（TMD）的异质结构通过结合与传统结构明显不同的独特物理性质，为实际应用提供了有吸引力的前景。在本文中，我们展示了一种用于生长双层 MoS-WS/WS 异质结构的三阶段化学气相沉积方法，底层为横向 MoS-中心/WS-边缘单层异质结构，顶层为 WS 单层。通过调整温度和载气流向，可以实现横向和垂直异质结构的交替生长。反向气流和更高生长温度的共同作用可以促进第二层在第一层异质结构的活性成核中心上的外延生长。通过使用定制的温度曲线，可以获得包括单层横向 MoS-WS 异质结构和双层横向 WS(2L)-MoS(2L)异质结构在内的单一异质结构。原子力显微镜、光致发光和拉曼映射研究清楚地表明，这些不同的异质结构样品具有高度的均匀性。这些结果为基于不同 TMD 材料的复杂异质结构的合成提供了一种有前途和有效的方法，这将极大地扩展异质结构家族并拓宽其应用。
