Fabrication and optimization of ITO-Ag co-sputtered nanocomposite films as plasmonic materials in the near-infrared region

摘要

Systematic study of magnetron sputtered silver-indium tin oxide (Ag-ITO) composite films has been carried out by altering the atomic ratio of silver in the co-sputtered films. The optimal micro-structure characteristic with smooth surface and tight junction between silver and ITO particles could be obtained by tuning Ag atomic ratio. Spectroscopic ellipsometry is applied in order to evaluate the plasmonic properties. Real and imaginary permittivity of the films are retrieved utilizing Drude-Lorentz dispersion model. The cross-over wavelength of the films, optimized to as low as around 1130 nm, exhibits high adjustability on the ratio of silver material and RTP process. Much lower imaginary permittivity as well as tunable real permittivity suggest the potentiality of Ag-ITO composite films as substituted plasmonic materials in the near-infrared region.