This thesis develops dielectric theory in multilayers and following cases have been considered: - Normal incidence on a multilayered slab with n isotropic layers. - Parallel incidence on a multilayered slab with n isotropic layers. - Normal and parallel incidence on a multilayered with n anisotropic layers, analysed in the non-retarded limit. In each case we have developed the appropriate transfer matrix recurrence relation and solved it exactly, using computer algebra (REDUCE and MATHEMATICA) as an essential guide. For all the problems listed above, we have obtained closed form solutions for the dispersion relations of surface and interface plasmons and for the angle-resolved energy-loss function. The energyloss spectrum is then obtained by integrating over wavevectors. The formulas we have derived are applied to real materials such as Al/Mg, Al/Al203, Al/Si02/Si, diamond and graphite.

No description available.

No description available.

Transition metal Dichalcogenide MoS2in the monolayer and few-layer form have generated intense interest in the fundamental and applied research community due to its surprisingly strong light-matter interactions, strong excitonic effect, and unique elec-tronic and chemical activity at the edges. In this thesis work, I have conducted a series of synergistic experimental and computational investigations focused on understanding the fundamental optical properties of few-layer MoS2(experiment with supporting computational calculations) and its potential application into the electrochemical reduction of CO2(computational)In the first part of the thesis, I show that sulfur vacancies affect the optical properties of few-layer thin films deposited using magnetron sputtering. In particular, I show that sulfur vacancies can obscure the well-defined A/B excitons in MoS2. Next, while contributing with the process of developing high-quality MoS2films, I designed an approach to accurately determine the optical constants by combining transmission spectroscopy with spectroscopic ellipsometry. The method, which we call Transmission-assisted spectroscopic ellipsometry (TASE), is demonstrated on high-quality MoS2films deposited on transparent and absorbing substrates. Next, Transmission spectroscopy combined with the Kramers-Kronig consistent optical model was employed to determine the complex dielectric function of few-layer MoS2in the broadband energy range of 0.7-6.5 eV. Optical transitions leading to peaks in the dielectric functions are assigned to the band structure. In particular, a new peak is observed and assigned at 4.5 eV in few-layer MoS2. Finally, I have examined the effectiveness of doped MoS2on the catalytic activity for CO reduction using density functional theory method. The structural calculation shows that doping Mo edge site of MoS2with transition metals that have higher work function than Mo atom results a lowering in the CO adsorption energy which suppresses the dissociation reaction and enhances the hydrogenation reaction. The Bader charge analysis shows that the dopant atom does not contribute to CO adsorption directly but it reduces the charge density at the edge atom that is indicated from the Density of states.

In this study, the electrical aging of 15 kV Ethylene Propylene Rubber (EPR) power cables, located in PVC pipes containing water, was conducted by ac voltage with switching impulses superimposed. The experiments provided a better understanding of the electrical aging phenomenon of EPR cable insulation. They also helped to assess the reliability of EPR cables used under such circumstances. EPR cable insulation was aged by rated ac voltage with switching impulses superimposed. The experiments also examined the degradation of EPR insulation by elevated ac voltage with switching impulses superimposed. Partial discharge parameters, capacitance and dissipation factor were measured at subsequent intervals during the aging process so as to understand the factors affecting aging process. After completion of the aging study, the remaining dielectric strength of tested cables was evaluated by ac breakdown voltage measurement.

We present the dielectric function of a bcc-In2O3 thin film in the wide spectral range from nearinfrared to vacuum-ultraviolet and for temperatures 10 K–300K, determined by spectroscopic ellipsometry. From the temperature dependence of electronic transition energies, we derive electron-phonon coupling properties and found hints that the direct parabolic band-band transitions involve In-d states. Further we discuss possible excitonic contributions to the dielectric function.

No description available.

No description available.

No description available.

A description of the apparatus used in microwave phase and diffraction measurements is contained in the first chapter of this thesis. The field was investigated by a phase technique and the point source of radiation reasonably well established. Several diffraction patterns about a dielectric and a conducting rod were taken at several distances behind the rod with E vector of the field parallel to the axis of the rod. These were qualitatively analysed and compared with the patterns of one other worker at 1.25 cm. Agreements and differences were noted. / Thesis / Master of Science (MS)