Duan Research Group

Hetero-integrated Nanostructures and Nanodevices


Van der Waals epitaxial growth and optoelectronics of large-scale WSe2/SnS2 vertical bilayer p–n junctions

Tiefeng Yang, Biyuan Zheng, Zhen Wang, Tao Xu, Chen Pan, Juan Zou, Xuehong Zhang, Zhaoyang Qi, Hongjun Liu, Yexin Feng, Weida Hu, Feng Miao, Litao Sun, Xiangfeng Duan, Anlian Pan

Nature Commun. 8, 1906 (2017)

High-quality two-dimensional atomic layered p–n heterostructures are essential for high-performance integrated optoelectronics. The studies to date have been largely limited to exfoliated and restacked flakes, and the controlled growth of such heterostructures remains a significant challenge. Here we report the direct van der Waals epitaxial growth of large-scale WSe2/SnS2 vertical bilayer p–n junctions on SiO2/Si substrates, with the lateral sizes reaching up to millimeter scale. Multi-electrode field-effect transistors have been integrated on a single heterostructure bilayer. Electrical transport measurements indicate that the field-effect transistors of the junction show an ultra-low off-state leakage current of 10−14 A and a highest on–off ratio of up to 107. Optoelectronic characterizations show prominent photoresponse, with a fast response time of 500 μs, faster than all the directly grown vertical 2D heterostructures. The direct growth of high-quality van der Waals junctions marks an important step toward high-performance integrated optoelectronic devices and systems.
UCLA, Department of Chemistry and Biochemistry
607 Charles E. Young Drive East, Box 951569
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E-mail: xduan@chem.ucla.edu