Atomic Layer Deposition of Al-Doped MoS2: Synthesizing a p-type 2D Semiconductor with Tunable Carrier Density

Vincent Vandalon; Marcel A Verheijen; Wilhelmus M M Kessels; Ageeth A Bol

doi:10.1021/acsanm.0c02167

Atomic Layer Deposition of Al-Doped MoS₂: Synthesizing a p-type 2D Semiconductor with Tunable Carrier Density

ACS Appl Nano Mater. 2020 Oct 23;3(10):10200-10208. doi: 10.1021/acsanm.0c02167. Epub 2020 Sep 23.

Authors

Vincent Vandalon¹, Marcel A Verheijen^{1

2}, Wilhelmus M M Kessels¹, Ageeth A Bol¹

Affiliations

¹ Applied Physics, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands.
² Eurofins Material Science Netherlands BV, 5656AE Eindhoven, The Netherlands.

Abstract

Extrinsically doped two-dimensional (2D) semiconductors are essential for the fabrication of high-performance nanoelectronics among many other applications. Herein, we present a facile synthesis method for Al-doped MoS₂ via plasma-enhanced atomic layer deposition (ALD), resulting in a particularly sought-after p-type 2D material. Precise and accurate control over the carrier concentration was achieved over a wide range (10¹⁷ up to 10²¹ cm^-3) while retaining good crystallinity, mobility, and stoichiometry. This ALD-based approach also affords excellent control over the doping profile, as demonstrated by a combined transmission electron microscopy and energy-dispersive X-ray spectroscopy study. Sharp transitions in the Al concentration were realized and both doped and undoped materials had the characteristic 2D-layered nature. The fine control over the doping concentration, combined with the conformality and uniformity, and subnanometer thickness control inherent to ALD should ensure compatibility with large-scale fabrication. This makes Al:MoS₂ ALD of interest not only for nanoelectronics but also for photovoltaics and transition-metal dichalcogenide-based catalysts.