Determining the impact of hydrofluoric acid on surface states of as-prepared and chemically modified Si nanocrystals

Oliinyk, Bohdan V.; Lysenko, V.; Алексеев, С. А.

doi:10.1039/c5ra24556g

Cited by 9 publications

(9 citation statements)

References 41 publications

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“…Therefore, the laser processing of PSi in HF-contained organic solution produces highly efficient colloidal Si-nc with considerably low defect density, as shown in Figure b (see also Figure ). The similar increase in the QE of Si-nc via an enhancement in the hydrosilylation reaction due to HF addition has also been reported in the literature. , The above-mentioned alkyl termination mechanism for the increased QE by the HF addition is schematically shown in Scheme .…”

Section: Resultssupporting

confidence: 80%

Improvement of Laser Processing for Colloidal Silicon Nanocrystal Formation in a Reactive Solvent

Nakamura

Adachi

et al. 2017

J. Phys. Chem. C

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We report the highly improvement of colloidal Si nanocrystal (Si-nc) formation by pulsed-UV-laser irradiation of porous silicon in a HF-contained organic solvent. The Si-nc in such reactive organic solvent exhibits higher photoluminescence quantum yield (∼50–70%) than that in an ordinary organic solvent without HF (∼20%). This enhancement of the quantum yield is caused by HF-induced removal of the surface oxidation layer and subsequent hydrogen termination of the Si surface. These reaction kinetics promote an efficient hydrosilylation between the hydrogen-terminated surface and an organic solvent, resulting in oxygen-free surface terminated by alkyl groups. Furthermore, the preparation yield in the HF-contained solvent is higher and the size distribution of Si-nc becomes more homogeneous than those in the ordinary solvent. These results can be attributed to efficient pulsed-laser-induced fragmentation by the removal of the oxidation layer on the porous Si target surface.

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Section: Resultssupporting

confidence: 80%

Improvement of Laser Processing for Colloidal Silicon Nanocrystal Formation in a Reactive Solvent

Nakamura

Adachi

et al. 2017

J. Phys. Chem. C

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“…Significant increase of the porosity under the HF treatment indicates that “refresh” procedure resulted not only in oxide removal but also in dissolution of the silicon, probably, of the defect-enriched subsurface layers. A similar phenomenon, i.e., Si surface defects removal under the action of HF accompanied with the conductivity increase, is described in our recent work [13]. …”

Section: Resultssupporting

confidence: 82%

Impact of Water Adsorption on Nonlinear Optical Properties of Functionalized Porous Silicon

et al. 2017

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The porous silicon (PS) surface modification diagnostics due to functionalization and water adsorption/desorption processes were provided by the self-action effects of picosecond range pulsed laser radiation at 1064 nm. It was shown that the PS surface functionalization—oxide removal, alkylation, and oxidation—resulted in a refractive nonlinear optical (NLO) response sign turn to self-focusing (Δn>0) versus the self-defocusing (Δn<0) observed in the aged PS. The sensitivity of the proposed technique was revealed to water adsorption/desorption from the chemically oxidized PS interface. For the dried PS, the self-defocusing effect with corresponding NLO cubic susceptibility Re(χ (3))∼−4.7·10−9 esu was observed versus the self-focusing one (∼5·10−8 esu) for the PS positioned in saturated water vapor at room temperature. The obtained results demonstrate high sensitivity and wide versatility of the proposed readout technique based on pulsed laser radiation self-action at 1064 nm to the PS surface modification monitoring/diagnostics applications.

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“…Both of these factors facilitate the formation of CFO and probably are efficient in surface defects passivation. The passivation, similarly as it occurs for p + -type por-Si under the action of HF, 74 resulted in the release of charge carriers trapped onto the surface defects. Increase in the carriers' concentration resulted in overall thinning of the SCR and highly porous filamentary por-SiC with small crystallites formation.…”

Section: Acs Applied Nano Materialsmentioning

confidence: 99%

Mesoporous SiC with Potential Catalytic Application by Electrochemical Dissolution of Polycrystalline 3C-SiC

Gryn

Nychyporuk

Bezverkhyy

et al. 2018

ACS Appl. Nano Mater.

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Electrochemical dissolution of highly doped (ρ ∼ 1 mΩ•cm, n-type) polycrystalline 3C-SiC in HF/H 2 O and HF/H 2 O/ethanol solutions allowed production of porous silicon carbide (por-SiC) and soluble carbon fluorooxide nanoparticles as a byproduct. The por-SiC is a crystalline material with large pore volume, surface area close to 100 m 2 g −1 , and open mesoporous structure. The surface of por-SiC is covered with a thin carbon-enriched layer, bearing carboxylic acid groups. Depending on the SiC resistivity, etchant composition, and current density, three different types of por-SiC morphology, namely, a macroporous tubular, mesoporous hierarchical, and mesoporous filamentary were revealed. A qualitative physical model of SiC electrochemical dissolution, based on the phenomena of quantum confinement, charge carriers trapping onto the surface defects, and the surface passivation, was proposed, and the model successfully interpreted the dependencies of por-SiC morphology and material balance on the etching conditions. The por-SiC is anticipated to be a prospective material for catalytic, nanofiltration, and sensing applications.

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Determining the impact of hydrofluoric acid on surface states of as-prepared and chemically modified Si nanocrystals

Abstract: The paper demonstrates an easy and cheap approach to chemical functionalization of silicon nanocrystal surface leading to enhancement of photoluminescence and electrical transport properties.

Cited by 9 publications

References 41 publications

Improvement of Laser Processing for Colloidal Silicon Nanocrystal Formation in a Reactive Solvent

Improvement of Laser Processing for Colloidal Silicon Nanocrystal Formation in a Reactive Solvent

Impact of Water Adsorption on Nonlinear Optical Properties of Functionalized Porous Silicon

Mesoporous SiC with Potential Catalytic Application by Electrochemical Dissolution of Polycrystalline 3C-SiC

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