Interactions of an electromagnetic wave with a sphere that is smaller than the wavelength can be accounted for by studying the dipole moments,... Show moreInteractions of an electromagnetic wave with a sphere that is smaller than the wavelength can be accounted for by studying the dipole moments, which are the valid explanation for the scattering characteristics in the frequency region known as the Rayleigh region. The semiconductor nanoparticle with a core-shell structure describes a specific geometry yielding tunable plasmon resonance of the nanostructure. This is achieved by varying the thickness of the dielectric material shell layer on a semiconductor core. The polarization of core-shell sphere induced by a dynamic field is studied both analytically and numerically. Dielectric function is used for the description of the response of bound charges to an applied field, resulting in the electric polarization, which has been employed to explicate scattering and absorption properties of particles over the years. However, this traditional model has some limitations in accounting for some aspects of polarization when mobile charges are present. By coupling the transport equations of the charge carriers to the Maxwell’s equations, we can derive the electric field, charge and the total induced dipole moment of a nano-core-shell particle. Results of calculations accomplished for elementary structures such as plates and spheres represented the screening of the internal field while dispersion and absorptions effects are revealed by the complex dipole moments. And the results in static and quasi-static field are shown. Equivalent circuits for the core-shell structures are obtained from carrier transport consideration, which can be employed to guide the synthesis of new nanoparticles with heterogeneous internal structures to achieve novel polarization properties for sensing and terahertz circuitry applications. Show less
