Speaker
Description
As silicon CMOS technology approaches scaling limits, two-dimensional (2D) semiconductors such as molybdenum disulfide (MoS$_2$) are being explored for next-generation transistor channels due to their excellent electrostatic control and reduced short-channel effects. However, achieving low contact resistance remains a key challenge, as Fermi level pinning (FLP) and van der Waals gaps in conventional top-contact geometries lead to significant Schottky barriers.
In this work, we present a computational study based on density functional theory (DFT) combined with the non-equilibrium Green’s function (NEGF) formalism to investigate edge-contact injection in MoS$_2$ transistors with channel lengths in the $12-15$ nm regime. Three contact paradigms are benchmarked: conventional Au edge contacts, phase-engineered $1T'-2H$ MoS$_2$ homojunctions, and semimetallic Bi contacts.
Using QuantumATK, we analyze the interfacial electronic structure and transport properties, focusing on band alignment, Schottky barrier formation, and interfacial transmission. Particular attention is given to the role of contact-induced states and orbital hybridization in facilitating carrier injection. The different contact paradigms are compared in terms of transmission efficiency and their ability to approach ohmic behavior in the short-channel regime.
By correlating atomistic interface properties with transport characteristics, this study identifies key interface features that mitigate Fermi level pinning and enhance carrier injection, providing insight into contact design strategies for sub-$15$ nm 2D electronic devices.