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A. Manivannan

Bio: A. Manivannan is an academic researcher from United States Department of Energy. The author has contributed to research in topics: Surface plasmon resonance & Plasmon. The author has an hindex of 3, co-authored 3 publications receiving 16 citations.

Papers
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TL;DR: In this paper, the optical response of a two-phase composite consisting of Au nanoparticles (AuNPs) in a nanocrystalline ZnO thin film matrix has been systematically studied and analyzed by the Bergman-Milton spectral density formalism.
Abstract: The optical response of a two-phase composite consisting of Au nanoparticles (AuNPs) in a nanocrystalline ZnO thin film matrix has been systematically studied and analyzed by the Bergman–Milton spectral density formalism. The real and imaginary parts of the effective dielectric function exhibited anomalous dispersion and absorption, respectively, at the characteristic localized surface plasmon resonance (LSPR) wavelength. A multilayer structure consisting of two AuNP–ZnO composite films separated by a thin ZnO film displayed a twofold increase in the absorption at LSPR (with negligible change in FWHM), which is attributed to the increase in the number density of the AuNPs resulting from the nanocrystalline nature of the ZnO film. The results have been used to correlate the spectral density function to the morphology of AuNPs in a ZnO matrix.

7 citations

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TL;DR: In-situ rapid thermal treatment during dc sputtering of ZnO film has been found to induce subtle changes in the morphology of AuNPs, thereby altering the profile of the plasmon band in the absorption spectra.
Abstract: The plasmonic behavior of metallic nanoparticles is explicitly dependent on their shape, size and the surrounding dielectric space. This study encompasses the influence of ZnO matrix, morphology of Au nanoparticles (AuNPs) and their organization on the optical behavior of ZnO/AuNPs-ZnO/ZnO/GP structures (GP: glass plate). These structures have been grown by a multiple-step physical process, which includes dc sputtering, thermal evaporation and thermal annealing. Different analytical techniques such as scanning electron microscopy, glancing angle X-ray diffraction, Rutherford backscattering spectrometry and optical absorption have been used to study the structures. In-situ rapid thermal treatment during dc sputtering of ZnO film has been found to induce subtle changes in the morphology of AuNPs, thereby altering the profile of the plasmon band in the absorption spectra. The results have been contrasted with a recent study on the spectral response of dc magnetron sputtered ZnO films embedded with AuNPs. Initial simulation results indicate that AuNPs-ZnO/Au/GP structure reflects/absorbs UV and infrared radiations, and therefore can serve as window coatings.

6 citations

Journal ArticleDOI
TL;DR: Combined analysis of GXRD and SPR data confirmed that while top Al layer enables controlling plasma oxidation of Ag, the setup enables monitoring the same and is a first of its kind for in situ SPR studies where creation of low pressure is a prerequisite.
Abstract: We report the surface plasmon resonance (SPR) measurements during plasma treatment of thin films by an indigenously designed setup. From the measurements on Al (6.3 nm)/Ag (38 nm) bi-layer at a pressure of 0.02 mbar, the SPR position was found to be shifted by ∼20° after a plasma treatment of ∼7 h. The formation of oxide layers during plasma oxidation was confirmed by glancing angle x-ray diffraction (GXRD) measurements. Combined analysis of GXRD and SPR data confirmed that while top Al layer enables controlling plasma oxidation of Ag, the setup enables monitoring the same. The setup designed is a first of its kind for in situ SPR studies where creation of low pressure is a prerequisite.

5 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the plasmonic effect significantly dominant to achieve maximum absorption enhancement g (λ ) at longer wavelengths (red and near infrared) and as comparable with Au nanoparticle on thin film Silicon.

35 citations

Journal ArticleDOI
Peifang Wang1, Di Wu1, Yanhui Ao1, Chao Wang1, Jun Hou1 
TL;DR: In this paper, the photocatalytic activity of the as-prepared samples was investigated by degradation of methylene blue under visible light irradiation, and the results showed that the synergistic effect of Au NPs and reduced graphene oxide (RGO) enhances visible light absorption range and transmits the hot electrons more efficiently.

21 citations

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TL;DR: In this paper, the Fabry-Perot (FP) modes of a dielectric cavity with a planar distribution of metal nanoparticles at one end have been studied numerically.
Abstract: Fabry-Perot (FP) modes of a dielectric cavity with a planar distribution of metal nanoparticles at one end have been studied numerically. An unusual enhancement in the strength of FP modes is observed close to the strong localized surface plasmon resonance of the metal nanoparticles. Experimental evidence for the numerical results has been provided by studying ZnO thin film cavities with Ag (Au) nanoparticles at one end. The enhancement in FP resonances has been interpreted in terms of a redefined cavity having a strongly dispersive adjacent medium.

19 citations

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TL;DR: In this article, the plasmonic layer of Au nanoparticles was electrodeposited onto WO 3 photoanodes in different configurations to enhance the photocurrent generation of the photo-electrochemical reaction.

14 citations

Journal ArticleDOI
Cuihua Zhao1, Junli Du1, Dewei Huang1, Yuqiong Li1, Jianhua Chen1, Weizhou Li1 
TL;DR: In this article, the absorption spectra of Ag/Al 2 O 3 thin films with 10 to 40% Ag content were investigated and it was shown that increasing Ag content over 40% results in partial connection of Ag particles, and hence the intensity of the absorption peak is weakened.

13 citations