Bandgap engineering in OH-functionalized silicon nanocrystals : interplay between surface functionalization and quantum confinement
Bürkle, Marius and Lozac'h, Mickaël and McDonald, Calum and Mariotti, Davide and Matsubara, Koji and Švrček, Vladimir (2017) Bandgap engineering in OH-functionalized silicon nanocrystals : interplay between surface functionalization and quantum confinement. Advanced Functional Materials, 27 (37). 1701898. ISSN 1616-301X (https://doi.org/10.1002/adfm.201701898)
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Abstract
In this work, a systematic first-principles study of the quasi-band structure of silicon nanocrystals (Si-NCs) is provided, focusing on bandgap engineering by combining quantum confinement of the electronic states with OH surface-functionalization. A mapping between the bandgap, Si-NC diameter, and the degree of hydroxide coverage is provided, which can be used as a guideline for bandgap engineering. Complementary to first-principles calculations, the photoluminescence (PL) wavelength of Si-NCs in the quantum-confinement regime is measured with well-defined diameters between 1 and 4 nm. The Si-NCs are prepared by means of a microplasma technique, which allows a surfactant-free engineering of the Si-NCs surface with OH groups. The microplasma treatment technique allows us to gradually change the degree of OH coverage, enabling us, in turn, to gradually shift the emitted light in the PL spectra by up to 100 nm to longer wavelengths. The first-principles calculations are consistent with the experimentally observed dependence of the wavelengths on the OH coverage and show that the PL redshift is determined by the charge transfer between the Si-NC and the functional groups, while on the other hand surface strain plays only a minor part.
ORCID iDs
Bürkle, Marius, Lozac'h, Mickaël, McDonald, Calum, Mariotti, Davide ORCID: https://orcid.org/0000-0003-1504-4383, Matsubara, Koji and Švrček, Vladimir;-
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Item type: Article ID code: 90258 Dates: DateEvent5 October 2017Published2 August 2017Published Online22 June 2017AcceptedSubjects: Science > Physics Department: Faculty of Engineering > Design, Manufacture and Engineering Management Depositing user: Pure Administrator Date deposited: 15 Aug 2024 09:42 Last modified: 24 Sep 2024 22:47 URI: https://strathprints.strath.ac.uk/id/eprint/90258