Schottky barriers, emission regimes and contact resistances in 2H-1T' MoS$_2$ lateral metal-semiconductor junctions from first-principles

TL;DR

This study uses first-principles calculations to analyze the transport properties and contact behaviors of 2H-1T' MoS₂ lateral junctions, revealing insights into Schottky barriers, interface types, and emission regimes relevant for FET contacts.

Contribution

It provides a detailed first-principles analysis of 2H-1T' MoS₂ junctions, highlighting their electrostatic response, contact resistance variations, and emission regimes, with improved experimental determination methods.

Findings

Schottky barrier heights respond similarly in 2D and 3D M-S junctions.

2H-1T' MoS₂ junctions are free from Fermi level pinning.

Armchair interfaces have better contact properties than zigzag.

Abstract

We have studied the finite bias transport properties of a 2H-1T' MoS$_2$ lateral metal-semiconductor (M-S) junction by non-equilibrium Green's functions calculations, aimed at contacting the 2D channel in a field effect transistor. Our results indicate that (a) despite the fundamentally different electrostatics of line and planar dipoles, the Schottky barrier heights respond similarly to changes in doping and applied bias in 2D and 3D M-S junctions, (b) 2H-1T' MoS$_2$ lateral junctions are free from Fermi level pinning, (c) armchair interfaces have superior contacting properties vs.\ zigzag interfaces, (d) 1T' contacts to $p$ channels will present a reduced contact resistance by a factor of 4-10 with respect to $n$ channels and (e) contacts to intermediately doped $n$ ($p$) channels operate in the field (thermionic) emission regime. We also provide an improved procedure to experimentally determine the emission regime in 2D material junctions.