Optical properties of DC sputtered titanium dioxide/gold thin films

Abstract

Titanium dioxide (TiO2) thin films have been generally accepted as an important material in the fields of photocatalysis, photovoltaic and photochromic. The efficiency of TiO2 films as an active layer in various applications strongly depends on their optical properties. In this present study, the optical properties of sputtered TiO2 thin films were modified using nanoparticles gold (Au) underlayer. TiO2 thin films with 100 nm thicknesses were prepared by DC magnetron sputtering on gold coated glass substrates with the estimated thickness approximately 2, 6 and 10 nm. The deposited TiO2/Au films were characterized using UV-Vis spectroscopy and photoluminescence (PL) spectroscopy. The transmittance of TiO2/Au film in visible region decreased from 87% to 50% when thickness of gold underlayer increased from 0 to about 10 nm. In addition, energy gap of TiO2/Au film from Tauc’s plot decreased with the increase of the thickness of gold underlayer while the wavelength of peak emission spectra obtained from PL were found to be increased. The modified optical properties indicated the probability of light absorption which may lead to the increase in electron-hole pair generation in this composite film.