RESUMO
Indium tin oxide (ITO) thin films doped with a volume ratio of 0.3% Ag were prepared by sputtering and subsequently annealed in temperatures of 200, 260, 300, 360, and 400 degrees C. The annealed films show increased transmittance in the visible wavelength range. The refractive index n and extinction coefficient k were extracted from simulating the transmittance spectra by using spectroscopic ellipsometry analysis method. The n values apparently increased in the whole wavelength range, but the k values were found to have almost no change in the near ultraviolet region after Ag doping. It is, therefore, proposed that the ITO:Ag combined with an ITO multilayer structure can be applied in special optical devices.
RESUMO
Ultrathin silver films (4.0, 6.2, 12.5, 26.2, 30.0 and 40.6 nm) were prepared by direct current sputtering deposition. The thicknesses and optical constants of the films were studied by spectroscopic ellipsometry. The Drude model combined with Lorentz Oscillator model was used in the optimization of the ellipsometric data. The results show that surface plasma resonance absorption (SPR) peaks appear in the spectra of extinction coefficient k for samples 1, 2, 3 and 4. The peak shifts to shorter wavelength with the reduction in film thickness. The wavelengths of the SPR for different films were calculated by the SPR theory and also compared with the experimental data.
