Bi–MoSe<sub>2</sub> Contacts in the Ultraclean\nLimit: Closing the Theory–Experiment Loop

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