Visible Light Emission from Nanocrystalline Silicon Embedded in CaF2 Layers on Si(111)

Masahiro WATANABE  Fumitaka IIZUKA  Masahiro ASADA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E79-C   No.11   pp.1562-1567
Publication Date: 1996/11/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Quantum Effect Devices and Their Fabrication Technologies)
Category: 
Keyword: 
nanocrystalline silicon,  quantum size effect,  visible light emission,  semiconductor-insulator heterostructure,  

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Summary: 
We report on the formation technique and the first observation of visible light emission from silicon nanoparticles (<10nm) embedded in CaF22 Iayers grown on Si(111) substrates by using codeposition of Si and CaF2. It is shown that the size and density of silicon particles embedded in the CaF2 layer can be controlled by varying the substrate temperature and the evaporation rates of CaF2 and Si. The photoluminescence (PL) spectra of Si nanoparticles embedded in CaF2 thin films were investigated. The blue or green light emissions obtained using a He-Cd laser (λ=325nm) could be seen with the naked eye even at room temperature for the first time. It is shown that the PL intensity strongly depends on growth conditions such as the Si:CaF2 flux ratio and the growth temperature. The PL spectra were also changed by in situ annealing process. These phenomena can be explained qualitatively by the quantum size effect of Si nanoparticles embedded in CaF2 barriers.