Ohmic Contact Engineering for Monolayer Transition-Metal Dichalcogenide Semiconductors

Ashish Gandhi^1*, Bo-Jiun Hsiao¹, Tai-Ting Lee¹, Ci-Juan Jhuo¹, Yi Xuan Chen¹, Jui-Pin Chen¹, Po-Wen Chiu^1,2

¹Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan
²Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan

* Presenter:Ashish Gandhi, email:acg.gandhi@gmail.com

The fascinating electronic properties of atomically thin two-dimensional (2D) monolayer transition-metal dichalcogenides (mTMDs) have attracted a great deal of attention for exploiting them as critical components in novel electronic devices. However, the Schottky barrier at the metal-mTMD interface leads to high contact resistance, hindering the practical application of 2D TMD transistors. To overcome the above issue, in this work, we have come up with a unique idea of utilizing hydrogen plasma to etch the top layer chalcogen atoms of a mTMD followed by electrode material deposition. The above electrode engineering leads to the formation of interface metallic bonds between metal and mTMD, which strongly perturbs the band structure of mTMD and vanishes the energy barriers at the interface. The work is in progress, and in the meeting, the author will present the experimental outcome on monolayer WS2 and WSe2 TMDs utilizing various electrode materials (Au, Pt, Ti, Cr, Al).

*Corresponding: pwchiu@ee.nthu.edu.tw (PWC)

Keywords: TMD, Ohmic, Schottky barrier, hydrogen plasma, metallic bonds