Li Jingtao, Ma Yang, Li Yufo, Li Shao-Sian, An Boxing, Li Jingjie, Cheng Jiangong, Gong Wei, Zhang Yongzhe
Faculty of Materials and Manufacturing, Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100124, China.
Faculty of Information Technology, Key Laboratory of Opto-Electronics Technology, Ministry of Education, Beijing University of Technology, Beijing 100124, China.
ACS Omega. 2022 Oct 19;7(43):39187-39196. doi: 10.1021/acsomega.2c05151. eCollection 2022 Nov 1.
The ultrathin feature of two-dimensional (2D) transition metal dichalcogenides (TMDs) has brought special performance in electronic and optoelectronic fields. When vertical and lateral heterojunctions are made using different TMD combinations, the original properties of premier TMDs can be optimized. Especially for lateral heterojunctions, their sharp interface signifies a narrow space charge region, leading to a strong in-plane built-in electric field, which may contribute to high separation efficiency of photogenerated carriers, good rectification behavior, self-powered photoelectric device construction, etc. However, due to the poor controllability over the synthesis process, obtaining a clean and sharp interface of the lateral heterojunction is still a challenge. Herein, we propose a simple chemical vapor deposition (CVD) method, which can effectively separate the growth process of different TMDs, thus resulting in good regulation of the composition change at the junction region. By this method, MoS-WS lateral heterojunctions with sharp interfaces have been obtained with good rectification characteristics, ∼10 on/off ratio, 1874% external quantum efficiency, and ∼120 ms photoresponse speed, exhibiting a better photoelectric performance than that of the lateral ones with graded junctions.
二维（2D）过渡金属二硫属化物（TMDs）的超薄特性在电子和光电子领域带来了特殊性能。当使用不同的TMD组合制成垂直和横向异质结时，优质TMDs的原始性能可以得到优化。特别是对于横向异质结，其清晰的界面意味着狭窄的空间电荷区，导致强的面内内置电场，这可能有助于光生载流子的高分离效率、良好的整流行为、自供电光电器件构建等。然而，由于合成过程的可控性差，获得横向异质结的清洁且清晰的界面仍然是一个挑战。在此，我们提出一种简单的化学气相沉积（CVD）方法，该方法可以有效分离不同TMDs的生长过程，从而实现对结区成分变化的良好调控。通过这种方法，已获得具有清晰界面的MoS-WS横向异质结，具有良好的整流特性、约10的开/关比、1874%的外量子效率和约120 ms的光响应速度，展现出比具有渐变结的横向异质结更好的光电性能。
