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Descripción
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| Si(0.6)Ge(0.4) nanoparticles/SiO2 multilayers, with layers of nanoparticles located at specific depths, for light emission applications have been deposited by LPCVD onto Si wafers at 390 ºC and 50 mTorr using GeH4, Si2H6 and O2. RTA treatments (700 to 1000 ºC, 0.5 to 10 min) were carried out to crystallize the nanoparticles. The samples were subsequently annealed in forming gas (FG) at 450 ºC. UV Raman spectroscopy, Transmission Electron Microscopy and cathodoluminescence analyses were performed. The as-deposited SiGe nanoparticles are amorphous and spherical, with uniform diameters ranging from 2 to 5 nm depending on the deposition time and with a density of around 1012 cm-2 in each layer. Nanoparticles of 5 nm were crystallized at 700 ºC, while 900 ºC were necessary to crystallize nanoparticles of 3 nm, in all cases without causing appreciable variations of their composition and size. Increasing the temperature to crystallize 2 nm nanoparticles causes Ge diffusion into the SiO2 matrix. The structures show luminescence at 400 nm from 80 K to room temperature. At 80 K it increases as: a) the size of the nanocrystals decreases, b) the thickness of the SiO2 interlayers increases and c) the number of periods in the structure increases. The maximum luminescence intensity was obtained in samples with nanoparticles of 3 nm and 35 nm thick oxide interlayers annealed at 900 °C for 1 min. The intensity is incremented by a 30 % after further annealing for 30 min in FG. | |
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Internacional
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Si |
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Nombre congreso
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European Materials Research Society 2007 Spring Meeting |
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Tipo de participación
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960 |
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Lugar del congreso
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Estrasburgo, Francia |
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Revisores
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Si |
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ISBN o ISSN
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DOI
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Fecha inicio congreso
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28/05/2007 |
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Fecha fin congreso
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01/06/2007 |
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