Area-Selective Growth of Two-Dimensional Mono- And Bilayer WS<sub>2</sub> for Field Effect Transistors
Lin-Yun Huang, Ming‐Yang Li, San‐Lin Liew, Shih‐Chu Lin, Ang‐Sheng Chou, Ming-Chun Hsu, Ching-Hao Hsu, Yu-Tung Lin, Po‐Sen Mao, Duen‐Huei Hou, Weicheng Liu, Chih‐I Wu, Wen‐Hao Chang, Han Wang, Lain‐Jong Li, Kung‐Hwa Wei
Abstract
Herein, we propose a novel approach for area-selective tunable growth of uniform monolayer or bilayer WS 2 on dielectric substrates through in situ conversion of a predeposited W metal pad to WO x initially and then to WS 2 mono- and bilayers. Compared with the various transfer methods that have been used previously for multilayer stacking, this direct-growth method has the advantages of producing cleaner interfaces and the capability of growing tunable layers on target substrates, thereby making it more suitable for manufacturing processes. The WS 2 bilayer displayed uniform optical properties, with the atomic arrangement between layers having an AA stacking order that are supposed to have higher mobility. We adopted these WS 2 monolayers and bilayers in field-effect transistors. Accordingly, this approach for highly area-selective growth of transition metal dichalcogenide monolayers and bilayers with metal pads and their in situ conversion appears to provide effective platforms for further device applications.