Optical and dielectric properties of (Zr 0.8,Sn 0.2)TiO 4 thin films prepared by sol–gel process

Abstract

(Zr 0.8,Sn 0.2)TiO 4 (ZST) thin films (∼314 nm) were grown on Pt/Ti/SiO 2/Si(1 0 0) and fused quartz glass substrates by sol–gel process. Microstructure and surface morphology of the ZST thin films have been studied by X-ray diffraction and atomic force microscopy. Optical properties of the ZST thin films were obtained by spectroscopic ellipsometry and UV–VIS spectrometry for the first time. An optical bandgap was found to be 3.57 eV of indirect-transition type. Low frequency (1 kHz–1 MHz) dielectric properties of the ZST thin films were also discussed. A temperature coefficient of capacitance of the ZST thin films is about 120.2 ppm °C −1 at 1 MHz. The dielectric constant and dissipation factor at 100 kHz are 26.6 and 0.01, respectively. The large dielectric loss compared with that of ZST ceramics is caused by the structure disorder in the thin film.