Temperature-dependent photoluminescence of surface-engineered silicon nanocrystals

Mitra, Somak; Švrček, Vladimír; Macías-Montero, Manuel; Velusamy, Tamilselvan; Mariotti, Davide

doi:10.1038/srep27727

Cited by 22 publications

(14 citation statements)

References 47 publications

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“…Herein, the PL emission peak I of the porous SiC can be attributed to the oxygen vacancy in the porous structures. The existence of oxygen vacancies, emitting in the blue light range of 410–470 nm, is a common phenomenon in semiconductor materials 28 , 35 – 37 . It has been reported that the luminescence peaks at 460 nm (2.7 eV) was derived from the triplet-to-ground transition of a neutral oxygen vacancy defect (O 3 ≡Si-Si≡O 3 ) 36 .…”

Section: Resultsmentioning

confidence: 99%

White Light Emission from Fluorescent SiC with Porous Surface

Fiordaliso

et al. 2017

Sci Rep

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AbstarctWe report for the first time a NUV light to white light conversion in a N-B co-doped 6H-SiC (fluorescent SiC) layer containing a hybrid structure. The surface of fluorescent SiC sample contains porous structures fabricated by anodic oxidation method. After passivation by 20 nm thick Al2O3, the photoluminescence intensity from the porous layer was significant enhanced by a factor of more than 12. Using a porous layer of moderate thickness (~10 µm), high-quality white light emission was realized by combining the independent emissions of blue-green emission from the porous layer and yellow emission from the bulk fluorescent SiC layer. A high color rendering index of 81.1 has been achieved. Photoluminescence spectra in porous layers fabricated in both commercial n-type and lab grown N-B co-doped 6H-SiC show two emission peaks centered approximately at 460 nm and 530 nm. Such blue-green emission phenomenon can be attributed to neutral oxygen vacancies and interface C-related surface defects generated dring anodic oxidation process. Porous fluorescent SiC can offer a great flexibility in color rendering by changing the thickness of porous layer and bulk fluorescent layer. Such a novel approach opens a new perspective for the development of high performance and rare-earth element free white light emitting materials.

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Section: Resultsmentioning

confidence: 99%

White Light Emission from Fluorescent SiC with Porous Surface

Fiordaliso

et al. 2017

Sci Rep

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“…Therefore, the PL properties should depend on the extent of surface oxidation of ncSi-H. Some previous studies have examined the PL emission with different surface configurations [20,21]. Bürkle et al studied theoretically and experimentally hydroxyl (OH) functionalized Si quantum dots (QDs) with different levels of oxidation [22].…”

Section: Introductionmentioning

confidence: 99%

Influence of Oxidation on Temperature-Dependent Photoluminescence Properties of Hydrogen-Terminated Silicon Nanocrystals

Ghosh

Shirahata

2020

Crystals

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In this study, we investigate temperature-dependent photoluminescence (PL) in three samples of hydrogen-terminated silicon nanocrystals (ncSi-H) with different levels of surface oxidation.ncSi-H was oxidized by exposure to ambient air for 0 h, 24 h, or 48 h. The PL spectra as a function of temperature ranging between room temperature (~297 K) and 4 K are measured to elucidate the underlying physics of the PL spectra influenced by the surface oxidation of ncSi-H. There are striking differences in the evolution of PL spectra according to the surface oxidation level. The PL intensity increases as the temperature decreases. ForncSi-H with a smaller amount of oxide, the PL intensity is nearly saturated at 90 K. In contrast, the PL intensity decreases even below 90 K for the heavilyoxidized ncSi-H. For all the samples, full-width at half maxima (FWHM)decreases as the temperature decreases. The plots of the PL peak energy as a function of temperature can be reproduced with an equation where the average phonon energy and other parameters are calculated.

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“…There is great interest in integrating opto-electronic and micro-photonic functionalities into the silicon-based platform, which has faced challenges due to the indirect bandgap nature of the silicon. For this reason allotropes of silicon and nanostructured Si have been widely investigated during the last few years as it offer an enhancement in the optical properties compared to bulk Si [1][2][3][4][5][6][7][8][9][10][11] and a pathway to obtain a direct band gap. Due to the enhancement in optical properties, nanostructured Si containing embedded Si nanocrystals is finding important new applications in nano-electronic and photonic devices including transistors, memories, and silicon based light emitting structures for optoelectronics and displays units etc [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…Due to the enhancement in optical properties, nanostructured Si containing embedded Si nanocrystals is finding important new applications in nano-electronic and photonic devices including transistors, memories, and silicon based light emitting structures for optoelectronics and displays units etc [12][13][14][15]. The modification of c-Si structure environment is expected to induce a more efficient luminescence than is found in indirect gap bulk c-Si, and also shift the emission from 1.1 eV into the desired visible region [6,16,17], a key goal in opto-electronics. Si nanocrystals offer a viable pathway for fabrication of direct band gap materials.…”

Section: Introductionmentioning

confidence: 99%

“…Si nanocrystals offer a viable pathway for fabrication of direct band gap materials. Various methods have been employed to produce ultra-fine silicon nanocrystals such as low pressure chemical vapour deposition [18], laser ablation [19,20], electrochemical anodization [5], rf-magnetron sputtering [6,21], rf-Plasma Enhanced CVD [22], microwave CVD [17], gas phase synthesis [23] etc.…”

Section: Introductionmentioning

confidence: 99%

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Quantum size effects and tunable visible photoluminescence in a-Si:H/nc-Si:H superlattices

Yadav

Agarwal

Biswas

2019

J Mater Sci: Mater Electron

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Quantum size effects are commonly observed in semiconductor nanocrystals and quantum dots. Here, we demonstrate unexpected quantum size effects in an unusual bulk system with multiple interfaces, consisting of alternating layers of nanocrystalline silicon (nc-Si:H) and amorphous silicon (a-Si:H) material thin films. The nc-Si:H layers consist of silicon nanocrystals embedded in an amorphous matrix, with an amorphouscrystalline interface separating the two structures. Plasma-enhanced chemical vapor deposition was utilized to grow nanocrystalline-amorphous silicon superlattices with a varying thickness of the nanocrystalline layer. Strong visible photoluminescence at room temperature was deconvoluted into individual peaks. As the nanocrystalline silicon layer thickness was increased from 5 to 20 nm, the photoluminescence spectra redshifted with the emission wavelength varying as d2 (d is the size of the nanocrystallites), the characteristic signature underlying quantum size effects. The size d of the nanocrystals was estimated by the measured shift of the Raman peak, and could be tuned by varying the thickness of the nc-Si:H layers. High resolution transmission electron microscopy show nanocrystals with a narrow size distribution, in an amorphous matrix. We also observe long wavelength photoluminescence from interfacial states that leads to persistent photconductivity. Nanocrystalline-amorphous superlattices offer a unique pathway for synthesizing embedded nanocrystals with controlled sizes and photonic signatures. Disciplines

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Temperature-dependent photoluminescence of surface-engineered silicon nanocrystals

Cited by 22 publications

References 47 publications

White Light Emission from Fluorescent SiC with Porous Surface

White Light Emission from Fluorescent SiC with Porous Surface

Influence of Oxidation on Temperature-Dependent Photoluminescence Properties of Hydrogen-Terminated Silicon Nanocrystals

Quantum size effects and tunable visible photoluminescence in a-Si:H/nc-Si:H superlattices

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