Substitutionally-doped 2D transition metal dichalcogenides are primed for next-generation device applications such as field effect transistors (FET), sensors, and optoelectronic circuits. In this work, we demonstrate substitutional Rhenium (Re) doping of MoS2 monolayers with controllable concentrations down to 500 parts-per-million (ppm) by metal-organic chemical vapor deposition (MOCVD). Surprisingly, we discover that even trace amounts of Re lead to a reduction in sulfur site defect density by 5-10x. Ab initio models indicate the free-energy of sulfur-vacancy formation is increased along the MoS2 growth-front when Re is introduced, resulting in an improved stoichiometry. Remarkably, defect photoluminescence (PL) commonly seen in as-grown MOCVD MoS2 is suppressed by 6x at 0.05 atomic percent (at.%) Re and completely quenched with 1 at.% Re. Furthermore, Re-MoS2 transistors exhibit up to 8x higher drain current and enhanced mobility compared to undoped MoS2 because of the improved material quality. This work provides important insights on how dopants affect 2D semiconductor growth dynamics, which can lead to improved crystal quality and device performance.
@article{arxiv.2302.00110,
title = {Dilute Rhenium Doping and its Impact on Intrinsic Defects in MoS2},
author = {Riccardo Torsi and Kyle T. Munson and Rahul Pendurthi and Esteban A. Marques and Benoit Van Troeye and Lysander Huberich and Bruno Schuler and Maxwell A. Feidler and Ke Wang and Geoffrey Pourtois and Saptarshi Das and John B. Asbury and Yu-Chuan Lin and Joshua A. Robinson},
journal= {arXiv preprint arXiv:2302.00110},
year = {2023}
}