Titanium nitride as light trapping plasmonic material in silicon solar cell

ZnO nanorod arrays co-loaded with Au nanoparticles and reduced graphene oxide: Synthesis, characterization and photocatalytic application

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.

Plasmon resonance mediated enhancement in Fabry-Pérot cavity modes

Enhanced plasmonic photoelectrochemical response of Au sandwiched WO3 photoanodes

Microstructure and strong optical absorption property of the Ag/Al2O3 nano-films

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.

Spectral response of nanocrystalline ZnO films embedded with Au nanoparticles

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.

Localized Surface Plasmon Resonance in Au Nanoparticles Embedded dc Sputtered ZnO Thin Films.

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.

A. Manivannan

Papers

Spectral response of nanocrystalline ZnO films embedded with Au nanoparticles

Localized Surface Plasmon Resonance in Au Nanoparticles Embedded dc Sputtered ZnO Thin Films.

Monitoring plasma treatment of thin films by surface plasmon resonance.