Semi-Metal Edge Contact for Barrier-Free Carrier Transport in MoS<sub>2</sub> Field Effect Transistors
Sungwon Lee, Xinbiao Wang, Hoseong Shin, Nasir Ali, Tien Dat Ngo, E. H. Hwang, Gil‐Ho Kim, Geun Young Yeom, Kenji Watanabe, Takashi Taniguchi, Won Jong Yoo
Abstract
The high contact resistance ( R c ) arising at the interface between a metal and a two-dimensional (2D) material presents a significant challenge to carrier transport in semiconductor devices based on 2D materials. The van der Waals gap and metal-induced gap states formed at the 2D interface give rise to an uncontrollable Schottky barrier, resulting in a high R c . In this study, we report the achievement of very low R c and ohmic behavior of molybdenum disulfide (MoS 2 ) field-effect transistors through the implementation of the edge contacts using semimetallic antimony (Sb). Our findings reveal that the edge contacts formed with Sb facilitate barrier-free carrier injection at the interface of MoS 2 devices, leading to highly efficient charge transport at room temperature, resulting in an unexpectedly further lowered R c (600 Ω·μm) at 10 K with a negligible Schottky barrier height. Further support for barrier-free ohmic transport is provided by density functional theory simulations, confirming that semimetallic Sb exhibits a very low density of states (DOS), with the Fermi level aligning well with the DOS of MoS 2 . Additionally, a comparison of linearity in output I – V characteristics with other metals confirms the superiority of the Sb edge contacts.