Atomic Layer Deposition of Al doped MoS2: Synthesizing a p-type 2D semiconductor with tunable carrier density

Extrinsically doped 2D semiconductors are essential for the fabrication of high-performance nanoelectronics amongst many other applications. Here we present a facile synthesis method for Al doped MoS2 via plasmaenhanced atomic-layer deposition (ALD) resulting in 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 in a combined transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) study. Sharp transitions in the Al concentration were realized and both doped and undoped material had the
characteristic 2D layered nature. The fine control over the doping concentration, combined with the conformallity and uniformity and sub-nm thickness control inherent to ALD should ensure compatibility with large scale fabrication. This makes Al:MoS2 ALD of interest for nanoelectronics but also for photovoltaics and TMD based catalysts.