1. Threshold voltage modulation in monolayer MoS2 field-effect transistors via selective gallium ion beam irradiation
- Author
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Mingkun Zhang, Yunshan Zhao, Yida Li, Changjie Zhou, Huili Zhu, Hao Shuai, Baoshan Tang, Hao Gong, Jin Feng Leong, and Weifeng Yang
- Subjects
Materials science ,business.industry ,Fermi level ,chemistry.chemical_element ,Acceptor ,Focused ion beam ,Ion ,Threshold voltage ,symbols.namesake ,chemistry ,Monolayer ,symbols ,Optoelectronics ,General Materials Science ,Field-effect transistor ,Gallium ,business - Abstract
Electronic regulation of two-dimensional (2D) transition metal dichalcogenides (TMDCs) is a crucial step towards next-generation optoelectronics and electronics. Here, we demonstrate controllable and selective-area defect engineering in 2D molybdenum disulfide (MoS2) using a focused ion beam with a low-energy gallium ion (Ga+) source. We find that the surface defects of MoS2 can be tuned by the precise control of ion energy and dose. Furthermore, the field-effect transistors based on the monolayer MoS2 show a significant threshold voltage modulation over 70 V after Ga+ irradiation. First-principles calculations reveal that the Ga impurities in the monolayer MoS2 introduce a defect state near the Fermi level, leading to a shallow acceptor level of 0.25 eV above the valence band maximum. This defect engineering strategy enables direct writing of complex pattern at the atomic length scale in a controlled and facile manner, tailoring the electronic properties of 2D TMDCs for novel devices.
- Published
- 2021