Issue 5, 2020

Towards the evaluation of defects in MoS2 using cryogenic photoluminescence spectroscopy

Abstract

Characterization of the type and density of defects in two-dimensional (2D) transition metal dichalcogenides (TMDs) is important as the nature of these defects strongly influences the electronic and optical properties of the material, especially its photoluminescence (PL). Defect characterization is not as straightforward as it is for graphene films, where the D and D′ Raman scattering modes easily indicate the density and type of defects in the graphene layer. Thus, in addition to the Raman scattering analysis, other spectroscopic techniques are necessary to perform detailed characterization of atomically thin TMD layers. We demonstrate that PL spectroscopy performed at liquid helium temperatures reveals the key fingerprints of defects in TMDs and hence provides valuable information about their origin and concentration. In our study, we address defects in chemical vapor deposition (CVD)-grown MoS2 monolayers. A significant difference is observed between the as-grown monolayers compared with the CVD-grown monolayers transferred onto a Si/SiO2 substrate, which contain extra defects due to the transfer process. We demonstrate that the temperature-dependent Raman and PL micro-spectroscopy techniques enable disentangling the contributions and locations of various defect types in TMD systems.

Graphical abstract: Towards the evaluation of defects in MoS2 using cryogenic photoluminescence spectroscopy

Supplementary files

Article information

Article type
Paper
Submitted
22 Aug 2019
Accepted
18 Nov 2019
First published
13 Dec 2019
This article is Open Access
Creative Commons BY license

Nanoscale, 2020,12, 3019-3028

Towards the evaluation of defects in MoS2 using cryogenic photoluminescence spectroscopy

T. Verhagen, V. L. P. Guerra, G. Haider, M. Kalbac and J. Vejpravova, Nanoscale, 2020, 12, 3019 DOI: 10.1039/C9NR07246B

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