Visible photoluminescence from oxidized Si nanometer-sized spheres: Exciton confinement on a spherical shell

Kanemitsu, Yoshihiko; Ogawa, T.; Shiraishi, Kenji; Takeda, Kyozaburo

doi:10.1103/physrevb.48.4883

Cited by 489 publications

(247 citation statements)

References 21 publications

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“…For example, oxidation of high surface area Si occurs readily in ambient and laboratory conditions and is frequently cited to coincide with sudden, drastic changes in the observed PL. 23,51,52,55,[65][66][67] However, the observed increase or decrease in emission energy that oxygen passivation causes varies from study to study.…”

Section: Effect Of Defects On Photoluminescence From Silicon Nanopartmentioning

confidence: 97%

“…68 Changes in the observed PL from nanocrystalline Si have also been attributed to changes in the surface oxidation of nanocrystalline Si domains. For example, in two studies conducted by Kanemitsu and coworkers, 65,70 the group provided evidence for carrier trapping by electronic states resulting from defects at the interface between Si NPs and an a-SiO 2 surface layer. In the latter study, originally non-photoluminescent Si NPs were observed to emit intense 750 nm PL (λ exc = 355 nm) following the formation of an a-SiO 2 surface layer.…”

Section: Effect Of Defects On Photoluminescence From Silicon Nanopartmentioning

confidence: 99%

“…For Si NPs, the most commonly suspected source of non-radiative decay is the Si-based radical trap state (also called a dangling bond). 13,49,57,65,67,[71][72][73] In fact, it has been suggested that dangling bonds form highly efficient non-radiative recombination centers, such that the presence of a single dangling bond in a Si nanocrystal is sufficient to prevent PL. 49 Experimentally, dangling bonds have been shown to be present both on the surface of silicon nanoparticles, 74 as well as at the crystal-oxide interface of oxidized Si NPs.…”

Section: Effect Of Defects On Photoluminescence From Silicon Nanopartmentioning

confidence: 99%

“…51,54,55,[57][58][59][60][61][62][63][64][65]123,124 These studies have frequently linked changes in surface composition to the development of electronically active (defect) states within the bandgap. If the defect states that form are radiative recombination centers, the Si NP suspension would be expected to exhibit new photoluminescence (PL) bands.…”

Section: Motivation For the Present Studymentioning

confidence: 99%

“…However, the formation of such a layer is difficult to achieve experimentally, and surface oxidation typically results in the formation of electronically active states within the bandgap. 23,51,52,55,63,[65][66][67][68]70 Alkyl-passivation has long been used in order to surface stabilize bulk and nanocrystalline silicon surfaces, in particular against ambient oxidation. Alkylpassivation is thought to have negligible effects on the photophysical properties of the Si domains, similar to hydride-passivation.…”

Section: Surface Defect Prevention In Silicon Nanoparticlesmentioning

confidence: 99%

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Investigation into Effects of Instability and Reactivity of Hydride-Passivated Silicon Nanoparticles on Interband Photoluminescence

Radlinger¹

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While silicon has long been utilized for its electronic properties, its use as an optical material has largely been limited due to the poor efficiency of interband transitions. However, discovery of visible photoluminescence (PL) from nanocrystalline silicon in 1990 triggered many ensuing research efforts to optimize PL from nanocrystalline silicon for optical applications. Currently, use of photoluminescent silicon nanoparticles (Si NPs) is commercially limited by: 1) the instability of the energy and intensity of the PL, and 2) the low quantum yield of interband PL from Si NPs.Herein, red-emitting, hydrogen-passivated silicon nanoparticles (H-Si NPs) were synthesized by thermally-induced disproportionation of a HSiCl 3 -derived (HSiO 1.5 )n polymer. The H-Si NPs produced by this method were then subjected to various chemical and physical environments to assess the long-term stability of the optical properties as a function of changing surface composition. This dissertation is intended to elucidate correlations between the reported PL instability and the observed changes in the Si NP surface chemistry over time and as a function of environment.First, the stability of the H-Si NP surface at slightly elevated temperatures towards reactivity with a simple alkane was probed. The H-Si NPs were observed by FT-IR spectroscopy to undergo partial hydrosilylation upon heating in refluxing hexane, in addition to varying degrees of surface oxidation. The unexpected reactivity of the Si surface in n-hexane supports the unstable nature of the H-Si NP surface, and furthermore implicates the presence of highly-reactive Si radicals on the surfaces of the Si NPs. We propose that reaction of alkene impurities with the Si surface radicals is largely responsible for the observed surface alkylation. However, we also present an alternate ii mechanism by which Si surface radicals could react with alkanes to result in alkylation of the surface.Next, the energy and intensity stability of the interband PL from H-Si NPs in the presence of a radical trap was probed. Upon addition of (2,2,6,6,-tetramethyl-piperidin-1-yl)oxyl (TEMPO), the energy and intensity of the interband transition was observed to change over time, dependent on the reaction conditions. First, when the reaction occurred at 4ºC with minimal light exposure, the interband transition exhibited a gradual hypsochromic shift to between 595 nm and 655 nm, versus the λ max of the original low energy emission peak at 700 nm, depending on the amount of TEMPO in the sample.Second, when the reaction proceeded at room temperature with frequent exposure to 360 nm irradiation, the original interband transition at 660 nm was quenched while a new peak at 575 nm developed. Based on all the data collected and analyzed, we assign the 595 -655 nm transition as due to interband exciton recombination from Si NPs with reduced diameters relative to the original Si NPs. We furthermore assign the 575 nm transition as due to an oxide-related defect state resulting from rapid oxidation of pho...

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Section: Effect Of Defects On Photoluminescence From Silicon Nanopartmentioning

confidence: 97%

Section: Effect Of Defects On Photoluminescence From Silicon Nanopartmentioning

confidence: 99%

Section: Effect Of Defects On Photoluminescence From Silicon Nanopartmentioning

confidence: 99%

Section: Motivation For the Present Studymentioning

confidence: 99%

Section: Surface Defect Prevention In Silicon Nanoparticlesmentioning

confidence: 99%

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Investigation into Effects of Instability and Reactivity of Hydride-Passivated Silicon Nanoparticles on Interband Photoluminescence

Radlinger¹

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Particle size control and optical properties of laser-synthesized silicon nanopowders

Botti

Celeste

Coppola

1998

Appl. Organometal. Chem.

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Silicon nanoparticles have been synthesized by heating reactant gases with a 500 W CO2 laser. A technique based on scattering of He–Ne laser light by particulates in a reaction flame has been developed for probing the particle size evolution during the process, in order to scale down the particle diameter (under 10 nm). The optical and structural properties of laser‐synthesized silicon nanopowders obtained in different runs are reported. © 1998 John Wiley & Sons, Ltd.

show abstract

Particle size control and optical properties of laser‐synthesized silicon nanopowders

Botti

Celeste

Coppola

1998

Appl. Organometal. Chem.

View full text Add to dashboard Cite

Silicon nanoparticles have been synthesized by heating reactant gases with a 500 W CO 2 laser. A technique based on scattering of He-Ne laser light by particulates in a reaction flame has been developed for probing the particle size evolution during the process, in order to scale down the particle diameter (under 10 nm). The optical and structural properties of laser-synthesized silicon nanopowders obtained in different runs are reported. #

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Visible photoluminescence from oxidized Si nanometer-sized spheres: Exciton confinement on a spherical shell

Cited by 489 publications

References 21 publications

Investigation into Effects of Instability and Reactivity of Hydride-Passivated Silicon Nanoparticles on Interband Photoluminescence

Investigation into Effects of Instability and Reactivity of Hydride-Passivated Silicon Nanoparticles on Interband Photoluminescence

Particle size control and optical properties of laser-synthesized silicon nanopowders

Particle size control and optical properties of laser‐synthesized silicon nanopowders

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