Substrate-directed synthesis of MoS2 nanocrystals with tunable dimensionality and optical properties

Tomojit Chowdhury; Jungkil Kim; Erick C Sadler; Chenyang Li; Seong Won Lee; Kiyoung Jo; Weinan Xu; David H Gracias; Natalia V Drichko; Deep Jariwala; Todd H Brintlinger; Tim Mueller; Hong-Gyu Park; Thomas J Kempa

doi:10.1038/s41565-019-0571-2

Substrate-directed synthesis of MoS₂ nanocrystals with tunable dimensionality and optical properties

Nat Nanotechnol. 2020 Jan;15(1):29-34. doi: 10.1038/s41565-019-0571-2. Epub 2019 Nov 18.

Authors

Affiliations

¹ Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA.
² Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA.
³ Department of Physics, Korea University, Seoul, Republic of Korea.
⁴ Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, USA.
⁵ Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA.
⁶ Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA.
⁷ Materials Science and Technology Division, United States Naval Research Laboratory, Washington, DC, USA.
⁸ Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA. tkempa@jhu.edu.
⁹ Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA. tkempa@jhu.edu.

PMID: 31740793
DOI: 10.1038/s41565-019-0571-2

Abstract

Two-dimensional transition-metal dichalcogenide (TMD) crystals are a versatile platform for optoelectronic, catalytic and quantum device studies. However, the ability to tailor their physical properties through explicit synthetic control of their morphology and dimensionality is a major challenge. Here we demonstrate a gas-phase synthesis method that substantially transforms the structure and dimensionality of TMD crystals without lithography. Synthesis of MoS₂ on Si(001) surfaces pre-treated with phosphine yields high-aspect-ratio nanoribbons of uniform width. We systematically control the width of these nanoribbons between 50 and 430 nm by varying the total phosphine dosage during the surface treatment step. Aberration-corrected electron microscopy reveals that the nanoribbons are predominantly 2H phase with zig-zag edges and an edge quality that is comparable to, or better than, that of graphene and TMD nanoribbons prepared through conventional top-down processing. Owing to their restricted dimensionality, the nominally one-dimensional MoS₂ nanocrystals exhibit photoluminescence 50 meV higher in energy than that from two-dimensional MoS₂ crystals. Moreover, this emission is precisely tunable through synthetic control of crystal width. Directed crystal growth on designer substrates has the potential to enable the preparation of low-dimensional materials with prescribed morphologies and tunable or emergent optoelectronic properties.

Abstract

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