Effect of Ag layer thickness on optical and electrical properties of ion-beam-sputtered TiO2/Ag/TiO2 multilayer thin film

TiO2/Ag/TiO2 multilayer films have been deposited by Ion-beam sputtering technique with different Ag thickness. X-ray reflectivity technique with 3-layer fitting model has been used to calculate thickness, density, and roughness of the multilayer films. Gaussian fitting of XRD and Raman data is used to detect the crystalline growth of films while FTIR data confirm the presence of metal layer in the films. A phonon confinement effect originating from decrease in crystallite size is also observed with blue shift in some of the Raman active modes. Effect of Ag layer thickness on optical and electrical properties of multilayer films has been presented including a comparative study of our data with previously reported work on TiO2/Ag/TiO2 transparent conducting oxides. Transmittance of multilayer films in visible region (550 nm) has increased from 65 to 81% with increase in Ag thickness. The band gaps calculated from Tauc plot of these films follow Burstein-Moss effect. Sheet resistance has decreased from 15.41 to 5.92 Omega/ while carrier concentration and mobility show an increasing trend from 5.94 x 10(21) to 1.35 x 10(22) and 6.83 to 13.72 cm(2)/Vs, respectively, with the increase in Ag mid-layer thickness. Haacke's Figure of Merit (FOM) is recorded to be 7.9 x 10(-3) Omega(-1).

Automated summary

TiO2/Ag/TiO2 multilayer films were fabricated using ion-beam sputtering technique, and the effect of different Ag thickness on the films was analyzed. The results showed that increasing Ag thickness can improve the transparency and electrical properties of the films, but it also leads to the phonon confinement effect caused by the decrease in crystallite size.