Bi-MoSe<sub>2</sub> Contacts in the Ultraclean Limit: Closing the Theory-Experiment Loop.

Liu, Yang; Liu, Song; Wang, Zhiying; Al-Bqerat, Ashraf Hasan Mohammad; Zangiabadi, Amirali; Perebeinos, Vasili; Hone, James · Nano Lett · 2024

basic_science · Level V

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Abstract

Achieving robust electrical contacts is crucial for realizing the promise of monolayer 2D semiconductors such as semiconducting transition metal dichalcogenides (s-TMDs) in electronics. Despite recent breakthroughs, a gap remains between the experimental and theoretical understanding of metal-s-TMDs contacts. This study explores bismuth semimetal contacts to monolayer MoSe<sub>2</sub>, using a platform that minimizes experimental sources of uncertainty; we combine contact-front and contact-end measurements to measure key parameters like specific resistivity (ρ<sub>c</sub>) and transfer length (<i>L</i><sub>t</sub>). We find that the resistivity of MoSe<sub>2</sub> under the contacts is enhanced due to charge transfer that can be modeled using a self-consistent approach. In contrast, <i>ab initio</i> calculations of the interlayer charge transfer rate are inconsistent with the measured value of ρ<sub>c</sub>, highlighting the need for new theoretical approaches.