Issue 24, 2024

Designing barrier-free metal/MoS2 contacts through electrene insertion

Abstract

Transition-metal dichalcogenides (TMDCs), including MoS2, have great potential in electronics applications. However, achieving low-resistance metal contacts is a challenge that impacts their performance in nanodevices due to strong Fermi-level pinning and the presence of a tunnelling barrier. As a solution, we explore a strategy of inserting monolayers of alkaline-earth sub-pnictide electrenes with a general formula of [M2X]+e (M = Ca, Sr, Ba; X = N, P, As, Sb) between the TMDC and the metal. These electrenes possess two-dimensional sheets of charge on their surfaces that can be readily donated when interfaced with a TMDC semiconductor, thereby lowering its conduction band below the Fermi level and eliminating the Schottky and tunnelling barriers. In this work, density-functional theory (DFT) calculations were performed for metal/electrene/MoS2 heterojunctions for all stable M2X electrenes and both Au and Cu metals. To identify the material combinations that provide the most effective Ohmic contact, the charge transfer, band structure, and electrostatic potential were computed. Linear correlations were found between the charge donated to the MoS2 and both the electrene surface charge and work function. Overall, Ca2N appears to be the most promising electrene for achieving an Ohmic metal/MoS2 contact due to its high surface charge density.

Graphical abstract: Designing barrier-free metal/MoS2 contacts through electrene insertion

Supplementary files

Article information

Article type
Paper
Submitted
16 Dec. 2023
Accepted
15 Apr. 2024
First published
22 Apr. 2024

Phys. Chem. Chem. Phys., 2024,26, 16947-16954

Designing barrier-free metal/MoS2 contacts through electrene insertion

M. Rafiee Diznab, A. F. Rumson, J. Maassen and E. R. Johnson, Phys. Chem. Chem. Phys., 2024, 26, 16947 DOI: 10.1039/D3CP06112D

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