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

• Published in: ACS nano Vol. 16; no. 4; pp. 6541 - 6551
• Main Authors: Wu, Qilong, Bagheri Tagani, Meysam, Zhang, Lijie, Wang, Jing, Xia, Yu, Zhang, Li, Xie, Sheng-Yi, Tian, Yuan, Yin, Long-Jing, Zhang, Wen, Rudenko, Alexander N, Wee, Andrew T. S, Wong, Ping Kwan Johnny, Qin, Zhihui
• Format: Journal Article
• Language: English
• Published: American Chemical Society 26-04-2022
• Subjects: WSe2; scanning tunneling spectroscopy; intercalation; twist; scanning tunneling microscopy; metal−2D semiconductor interface
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.2c00916

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.