Molecular interaction of ozone with silicon nanocrystallites: a new method to excite visible luminescence

Кузнецов, С. Н.; Saren, Andrey; Pikulev, V. B.; Gardin, Yu. E.; Gurtov, V. A.

doi:10.1016/s0169-4332(02)00187-3

Cited by 9 publications

(4 citation statements)

References 15 publications

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“…Such a model of the backbond oxidation is in accordance with measurements of oxidized surfaces [53]. For Si NCs the backbond oxidation without destroying the Si-H surface bonds is supported by highresolution electron energy loss spectroscopy (HREELS) [53] and infrared (IR) absorption measurements [54]. After the oxygen insertion in the Si-Si bonds, large atomic forces and stresses arise in the system due to the short Si-O bond lengths of about 1.17 Å.…”

Section: Modelling Of Nanocrystals Capping Shells and Surface Termisupporting

confidence: 71%

Optical properties of Si and Ge nanocrystals: Parameter‐free calculations

Ramos

Weissker

Furthmüller

et al. 2005

Physica Status Solidi (b)

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An overview is given on the electronic and optical properties of Si and Ge nanocrystals. We model freestanding Si and Ge nanocrystals passivated with H, with up to 363 group-IV atoms and 276 H and oxidized nanocrystals with additional silicon oxide shells, e.g. Si 41 (O 60 Si 42 )(O 108 Si 64 )H 148 . The results discussed are based on parameter-free calculations for relaxed atomic structures. The electronic states and the many-body effects are considered within the density-functional theory and the supercell method. Energy gaps are described within the Kohn-Sham independent-particle picture and within the independentquasiparticle picture, whereas electronic excitations are treated within the delta self-consistent method by pair excitation energies. The projector-augmented wave method allows the calculation of optical matrix elements, oscillator strengths, optical spectra, and radiative lifetimes. We discuss quantum confinement, structural relaxation, oxidation, and the role of defects in oxidized Si NCs.

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Section: Modelling Of Nanocrystals Capping Shells and Surface Termisupporting

confidence: 71%

Optical properties of Si and Ge nanocrystals: Parameter‐free calculations

Ramos

Weissker

Furthmüller

et al. 2005

Physica Status Solidi (b)

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“…The effect is permanent, since no PL intensity recovery in the 5 days following the UV-ozone treatment was detected, see the area with a shaded background in figure 7(a). Ozone is known to oxidize Si-NCs, reducing their size, therefore causing a blue-shift of the PL peak, for the case of the QC effect [13,19,25]. Surprisingly, in our case, the ozone treatment resulted in a pronounced red-shift of the PL peak position, as can be seen from figure 7(b).…”

Section: Resultssupporting

confidence: 44%

“…During the experiment the samples were placed in front of a deuterium UV lamp, which stably generated approximately 1 ppm ozone in the proximity to the sample surface. Sometimes, after the oxidation-cycle, samples were held in a HF(50%) vapour for several minutes in order to refresh the Si surface by etching away SiO x , similar to [19].…”

Section: Experimental Techniquesmentioning

confidence: 99%

Origin of visible photoluminescence from arrays of vertically arranged Si-nanopillars decorated with Si-nanocrystals

et al. 2012

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Arrays of vertically aligned Si-nanopillars, with average diameters of 100 nm and 5 μm length, have been prepared by wet chemical etching of crystalline silicon in a special manner. Samples with smooth- and porous-walled nanopillars have been studied. In the case of the latter, Si-nanocrystals, passivated with SiO(x), decorating the surface of the nanopillars are identified by the means of TEM and FTIR. When excited by UV-blue light, the porous-walled Si-nanopillars are found to have a strong broad visible emission band around 1.8 eV with a nearly perfect Gaussian shape, μs luminescence lifetimes, minor emission polarization and a non-monotonic temperature dependence of luminescence. The Si-nanocrystal surface is found to be responsible for the luminescence. The red-shift of the emission maximum and the luminescence quenching induced by oxidation in UV-ozone confirm this assumption. A model of luminescence involving UV photon absorption by Si-nanocrystals with subsequent exciton radiative recombination on defect sites in SiO(x) covering Si-nanocrystals has been proposed. Possible applications of the nanopillar arrays are discussed.

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“…[1] Our data on the effect of ozone on nanostructured Si layers gave evidence in favor of a unified mechanism of radiative relaxation in both photo-and ozone-induced luminescence. [2] However, previous results were obtained on thick (> 5 mm) layers of nanostructured Si. For such thicknesses, the effect of in-depth inhomogeneity is observed owing to the electrochemical method of preparation.…”

Section: Introductionmentioning

confidence: 92%

Excitonic Chemiluminescence in Si and CdSe Nanocrystals Induced by their Interaction with Ozone

et al. 2011

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The results of a systematic study of spectral and kinetic patterns of ozone-adsorption-induced luminescence (AL) in nanostructured Si and, for the first time, in colloidal CdSe/ZnS quantum dots (QDs) are reported and compared with photoluminescence (PL) of the same structures. The common excitonic nature of light emission under ozone chemisorption and photoexcitation is confirmed by excellent coincidence of AL and PL emission bands. This coincidence is maintained during correlated quenching of AL and PL emission caused by nonradiative defects generated under ozone adsorption. A possible mechanism for energy conversion is proposed in the framework of an exothermic oxidation reaction of core materials caused by ozone. The significant role of the quantum confinement effect differentiates the observed phenomenon from well-known chemiluminescence in molecular systems. This research establishes a physicochemical basis for the development of a gas sensor with high selectivity to ozone. Also, our findings may be useful for testing core-shell colloidal QDs with ozone.

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Molecular interaction of ozone with silicon nanocrystallites: a new method to excite visible luminescence

Cited by 9 publications

References 15 publications

Optical properties of Si and Ge nanocrystals: Parameter‐free calculations

Optical properties of Si and Ge nanocrystals: Parameter‐free calculations

Origin of visible photoluminescence from arrays of vertically arranged Si-nanopillars decorated with Si-nanocrystals

Excitonic Chemiluminescence in Si and CdSe Nanocrystals Induced by their Interaction with Ozone

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