1. Enhanced quantum efficiency from a mosaic of two dimensional MoS2formed onto aminosilane functionalised substrates
- Author
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Yichao Wang, Ivan S. Cole, Jian Zhen Ou, Paul Atkin, Benjamin J. Carey, Torben Daeneke, Enrico Della Gaspera, Kourosh Kalantar-zadeh, Qiaoliang Bao, Yupeng Zhang, Zai-Quan Xu, Kyle J. Berean, and Rhiannon M. Clark
- Subjects
Potential well ,Materials science ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Nanomaterials ,Chemical engineering ,chemistry ,Molybdenum ,Monolayer ,Microscopy ,General Materials Science ,Quantum efficiency ,0210 nano-technology ,Spectroscopy ,Stoichiometry - Abstract
Developing scalable methods of growing two dimensional molybdenum disulphide (2D MoS2) with strong optical properties, on any desired substrates, is a necessary step towards industrial uptake of this material for optical applications. In this study, Si/SiO2 substrates were functionalised using self-assembled monolayers of three different aminosilanes with various numbers of amine groups and molecular lengths as underlayers for enhancing the adherence of the molybdenum precursor. The tetrahedral [MoS4](2-) anion groups from the molybdenum precursor were bonded on these silanised Si/SiO2 substrates afterwards. The substrates were then treated with a combined thermolysis and sulphurisation step. The results showed that silanisation of the substrates using the longest chains and the largest number of amine groups provided a good foundation to grow quasi 2D MoS2 made from adjacent flakes in a mosaic formation. Microscopy and spectroscopy investigations revealed that these quasi 2D MoS2 formed using this long chain aminosilane resulted in flakes with lateral dimensions in micron and submicron ranges composed of adjoining MoS2 pieces of 20 to 60 nm in lateral dimensions, dominantly made of 3 to 5 MoS2 fundamental layers. The obtained quasi 2D MoS2 shows a high internal quantum efficiency of 2.6% associated with the quantum confinement effect and high stoichiometry of the adjoining nanoflakes that form the structure of the sheets. The synthesis technique in this study is reliable and facile and offers a procedure to form large, scalable and patternable quasi 2D MoS2 sheets on various substrates with enhanced optical properties for practical applications.
- Published
- 2016