Optical constants and band gap expansion of size controlled silicon nanocrystals embedded in SiO2 matrix

Yu, Xingwen; Zhang, R.J.; Xu, Zhi; Zhang, D.X.; Zhao, Haibin; Zheng, Yuanzhou; Chen, L.Y.

doi:10.1016/j.jnoncrysol.2011.06.027

Cited by 7 publications

(3 citation statements)

References 31 publications

(50 reference statements)

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“…It is obviously found that the value of band gap declines from 3.718 to 3.417 eV with the increasing thickness (Fig. 4d ), as a result of quantum confinement effect [ 13 , 30 ]. The decrease of the size of material leads to the increase of the band gap.…”

Section: Resultsmentioning

confidence: 99%

Optical Constants and Band Gap Evolution with Phase Transition in Sub-20-nm-Thick TiO2 Films Prepared by ALD

et al. 2017

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Titanium dioxide (TiO2) ultrathin films with different thicknesses below 20 nm were grown by atomic layer deposition (ALD) on silicon substrates at 300 °C. Spectroscopic ellipsometry (SE) measurements were operated to investigate the effect of thickness on the optical properties of ultrathin films in the spectra range from 200 to 1000 nm with Forouhi–Bloomer (F-B) dispersion relation. It has been found that the refractive index and extinction coefficient of the investigated TiO2 ultrathin film increase while the band gap of TiO2 ultrathin film decreases monotonically with an increase in film thickness. Furthermore, with the purpose of studying the temperature dependence of optical properties of TiO2 ultrathin film, the samples were annealed at temperature from 400 to 900 °C in N2 atmosphere. The crystalline structure of deposited and annealed films was deduced by SE and supported by X-ray diffraction (XRD). It was revealed that the anatase TiO2 film started to transform into rutile phase when the annealing temperature was up to 800 °C. In this paper, a constructive and effective method of monitoring the phase transition in ultrathin films by SE has been proposed when the phase transition is not so obvious analyzed by XRD.

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Section: Resultsmentioning

confidence: 99%

Optical Constants and Band Gap Evolution with Phase Transition in Sub-20-nm-Thick TiO2 Films Prepared by ALD

et al. 2017

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“…These results are tabulated in Table 1. authors [2], [6]- [9]. Optical bandgap, ETauc is observed to be greater than that estimated from peak of PL spectra (EpL).…”

Section: Optic Al Bandg Ap Tunabilitymentioning

confidence: 99%

“…Half-filled symbols represent, ETauc while the solid symbols indicate the optical bandgap estimated from peak of PL spectra of various authors[2], [6]-[9].…”

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confidence: 99%

Optical bandgap tuning of ICPCVD-made silicon nanocrystals for next generation photovoltaics

Mavilla¹,

Dharmendra²,

Solanki

et al. 2012

2012 38th IEEE Photovoltaic Specialists Conference

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Superior optical properties of Si-Nanocrystals (Si NCs) compared to bulk Si, particularly tunability of bandgap by controlling size, can be exploited for realizing next generation "all-Si" tandem solar cells [1]. In this study, we present optical bandgap tunability of Si-NCs made by Inductively Coupled Plasma Enhanced Chemical Vapor Deposition (ICPCVD) using Si02/SiOx superlattice approach [2]. Deposition time of SiOx sublayer, and hence the related thickness (TSRO), was used as a variable parameter to realize Si-NCs of varying sizes. All multilayer (ML) samples were subsequently furnace annealed at 900°C, to allow for Si-NC formation. Formation of Si-NCs was confirmed by Raman spectroscopy. Transmittance, reflectance and absorptance spectra indicated gradual increase of bandgap with decreasing Ts RO. Optical bandgap, ETauc, estimated usingTauc analysis showed an increase in optical bandgap from 1.45 eV to 2.5 eV, as TSRO was varied from 10 nm to 2 nm respectively.

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Spectroscopic ellipsometry study of Si nanocrystals embedded in a SiO matrix: Modeling and optical characterization

İlday

Nogay

Turan

2014

Applied Surface Science

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Optical constants and band gap expansion of size controlled silicon nanocrystals embedded in SiO2 matrix

Cited by 7 publications

References 31 publications

Optical Constants and Band Gap Evolution with Phase Transition in Sub-20-nm-Thick TiO2 Films Prepared by ALD

Optical Constants and Band Gap Evolution with Phase Transition in Sub-20-nm-Thick TiO2 Films Prepared by ALD

Optical bandgap tuning of ICPCVD-made silicon nanocrystals for next generation photovoltaics

Spectroscopic ellipsometry study of Si nanocrystals embedded in a SiO matrix: Modeling and optical characterization

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