Improved luminescence properties of MoS2 monolayers grown via MOCVD: role of pre-treatment and growth parameters

Fabrication of transition metal dichalcogenides (TMDCs) via metalorganic chemical vapor deposition (MOCVD) represents one of the most attractive routes to large-scale 2D material layers. Although good homogeneity and electrical conductance have been reported recently, the relation between growth par...

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Bibliographic Details
Published in:Nanotechnology 2018-05, Vol.29 (29), p.295704-295704
Main Authors: Andrzejewski, D, Marx, M, Grundmann, A, Pfingsten, O, Kalisch, H, Vescan, A, Heuken, M, Kümmell, T, Bacher, G
Format: Article
Language:English
Subjects:
MOCVD
MoS
MOVPE
photoluminescence
Raman spectroscopy
transition metal dichalcogenides
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Summary:Fabrication of transition metal dichalcogenides (TMDCs) via metalorganic chemical vapor deposition (MOCVD) represents one of the most attractive routes to large-scale 2D material layers. Although good homogeneity and electrical conductance have been reported recently, the relation between growth parameters and photoluminescence (PL) intensity-one of the most important parameters for optoelectronic applications-has not yet been discussed for MOCVD TMDCs. In this work, MoS2 is grown via MOCVD on sapphire (0001) substrates using molybdenum hexacarbonyl (Mo(CO)6, MCO) and di-tert-butyl sulphide as precursor materials. A prebake step under H2 atmosphere combined with a reduced MCO precursor flow increases the crystal grain size by one order of magnitude and strongly enhances PL intensity with a clear correlation to the grain size. A decrease of the linewidth of both Raman resonances and PL spectra down to full width at half maxima of 3.2 cm−1 for the E2g Raman mode and 60 meV for the overall PL spectrum indicate a reduced defect density at optimized growth conditions.
ISSN:0957-4484
1361-6528
DOI:10.1088/1361-6528/aabbb9