One-Dimensional Edge Contacts to Two-Dimensional Transition-Metal Dichalcogenides: Uncovering the Role of Schottky-Barrier Anisotropy in Charge Transport across <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:msub><mml:mrow><mml:mi>Mo</mml:mi><mml:mi mathvariant="normal">S</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:math>/Metal Interfaces
Kamyar Parto, Arnab Pal, Tanmay Chavan, Kunjesh Agashiwala, Chao‐Hui Yeh, Wei Cao, Kaustav Banerjee
Abstract
Low-resistance ohmic contacts are a prerequisite for implementing two-dimensional transition-metal dichalcogenides (2D TMDs) in a host of applications. Edge contacts offer unique advantages, yet their electrical properties are not fully understood. Employing an $a\phantom{\rule{0}{0ex}}b$ $i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o$ framework, the authors find that edge contacts to monolayer MoS${}_{2}$ are pinned to a charge-neutrality level close to the valence band and are $p$-type---unlike typical $n$-type top contacts. This anisotropy in Fermi-level pinning complicates conduction through metal-TMD interfaces and affects design guidelines for low-resistance contacts. Challenges, potential mitigating solutions, and opportunities that leverage this anisotropy are discussed.