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Electronic Tuning in WSe2/Au via van der Waals Interface Twisting and Intercalation

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journal contribution
posted on 23.03.2022, 12:04 authored by Qilong Wu, Meysam Bagheri Tagani, Lijie Zhang, Jing Wang, Yu Xia, Li Zhang, Sheng-Yi Xie, Yuan Tian, Long-Jing Yin, Wen Zhang, Alexander N. Rudenko, Andrew T. S. Wee, Ping Kwan Johnny Wong, Zhihui Qin
The transition metal dichalcogenide (TMD)–metal interfaces constitute an active part of TMD-based electronic devices with optimized performances. Despite their decisive role, current strategies for nanoscale electronic tuning remain limited. Here, we demonstrate electronic tuning in the WSe2/Au interface by twist engineering, capable of modulating the WSe2 carrier doping from an intrinsic p-type to n-type. Scanning tunneling microscope/spectroscopy gives direct evidence of enhanced interfacial interaction induced doping in WSe2 as the twist angle with respect to the topmost (100) lattice of gold changing from 15 to 0°. Taking advantage of the strong coupling interface achieved this way, we have moved a step further to realize an n–p–n-type WSe2 homojunction. The intrinsic doping of WSe2 can be recovered by germanium intercalation. Density functional theory calculations confirm that twist angle and intercalation-dependent charge transfer related doping are involved in our observations. Our work offers ways for electronically tuning the metal–2D semiconductor interface.