Zhang Xiumei, Huangfu Luyao, Gu Zhengjian, Xiao Shaoqing, Zhou Jiadong, Nan Haiyan, Gu Xiaofeng, Ostrikov Kostya Ken
School of Science, Jiangsu Provincial Research Center of Light Industrial Optoelectronic Engineering and Technology, Jiangnan University, Wuxi, 214122, China.
Engineering Research Center of IoT Technology Applications (Ministry of Education), Department of Electronic Engineering, Jiangnan University, Wuxi, 214122, China.
Small. 2021 May;17(18):e2007312. doi: 10.1002/smll.202007312. Epub 2021 Mar 18.
The controllable large-area growth of single-crystal vertical heterostructures based on 2D transition metal dichalcogenides (TMDs) remains a challenge. Here, large-area vertical MoS /WS heterostructures are synthesized using single-step confined-space chemical vapor epitaxy. The heterostructures can evolve into two different kinds by switching the H flow on and off: MoS /WS heterostructures with multiple WS domains can be achieved without introducing the H flow due to the numerous nucleation centers on the bottom MoS monolayer during the transition stage between the MoS and WS monolayer growth. In contrast, isolated MoS /WS heterostructures with single WS domain can be obtained with introducing the H flow due to the reduced nucleation centers on the bottom MoS monolayer arising from the hydrogen etching effect. Both the two kinds of the vertical MoS /WS heterostructures feature high quality. The photodetectors based on the isolated MoS /WS heterostructures exhibit a high responsivity of 68 mA W and a short response time of 35 ms. This single-step chemical vapor epitaxy can be used to synthesize vertical MoS /WS heterostructures with high production efficiency. The new epitaxial growth approach may open new pathways to fabricate large-area heterostructures made of different 2D TMDs monolayers of interest to electronics, optoelectronics, and other applications.
基于二维过渡金属二硫属化物（TMDs）的单晶垂直异质结构的可控大面积生长仍然是一个挑战。在此，使用单步受限空间化学气相外延法合成了大面积垂直MoS₂/WS₂异质结构。通过打开和关闭H气流，异质结构可以演变成两种不同的类型：在MoS₂和WS₂单层生长的过渡阶段，由于底部MoS₂单层上有大量成核中心，在不引入H气流的情况下可以实现具有多个WS₂域的MoS₂/WS₂异质结构。相比之下，由于氢蚀刻效应导致底部MoS₂单层上的成核中心减少，在引入H气流的情况下可以获得具有单个WS₂域的孤立MoS₂/WS₂异质结构。这两种垂直MoS₂/WS₂异质结构均具有高质量。基于孤立MoS₂/WS₂异质结构的光电探测器表现出68 mA W的高响应度和35 ms的短响应时间。这种单步化学气相外延法可用于高效合成垂直MoS₂/WS₂异质结构。这种新的外延生长方法可能为制造由不同二维TMDs单层构成的大面积异质结构开辟新途径，这些异质结构对电子学、光电子学及其他应用具有重要意义。
