Issue 43, 2020

Understanding metal organic chemical vapour deposition of monolayer WS2: the enhancing role of Au substrate for simple organosulfur precursors

Abstract

We find that the use of Au substrate allows fast, self-limited WS2 monolayer growth using a simple sequential exposure pattern of low cost, low toxicity precursors, namely tungsten hexacarbonyl and dimethylsulfide (DMS). We use this model reaction system to fingerprint the technologically important metal organic chemical vapour deposition process by operando X-ray photoelectron spectroscopy (XPS) to address the current lack of understanding of the underlying fundamental growth mechanisms for WS2 and related transition metal dichalcogenides. Au effectively promotes the sulfidation of W with simple organosulfides, enabling WS2 growth with low DMS pressure (<1 mbar) and a suppression of carbon contamination of as-grown WS2, which to date has been a major challenge with this precursor chemistry. Full WS2 coverage can be achieved by one exposure cycle of 10 minutes at 700 °C. We discuss our findings in the wider context of previous literature on heterogeneous catalysis, 2D crystal growth, and overlapping process technologies such as atomic layer deposition (ALD) and direct metal conversion, linking to future integrated manufacturing processes for transition metal dichalcogenide layers.

Graphical abstract: Understanding metal organic chemical vapour deposition of monolayer WS2: the enhancing role of Au substrate for simple organosulfur precursors

Supplementary files

Article information

Article type
Paper
Submitted
07 Sept. 2020
Accepted
27 Okt. 2020
First published
28 Okt. 2020
This article is Open Access
Creative Commons BY license

Nanoscale, 2020,12, 22234-22244

Understanding metal organic chemical vapour deposition of monolayer WS2: the enhancing role of Au substrate for simple organosulfur precursors

Y. Fan, K. Nakanishi, V. P. Veigang-Radulescu, R. Mizuta, J. C. Stewart, J. E. N. Swallow, A. E. Dearle, O. J. Burton, J. A. Alexander-Webber, P. Ferrer, G. Held, B. Brennan, A. J. Pollard, R. S. Weatherup and S. Hofmann, Nanoscale, 2020, 12, 22234 DOI: 10.1039/D0NR06459A

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