Investigation of structural, morphological, and dielectric properties of BaSnO3 ceramics and thin films prepared by sol-gel method

Abstract

This work intends to compare the structural, morphological and frequency (20 Hz–1 MHz) and temperature (30 °C–300 °C) dependent dielectric properties of BaSnO3 ceramics and thin films. The BaSnO3 solution was prepared by sol-gel method. Thin films were deposited by spin-coating on Pt/Ti/SiO2/Si substrates. The ceramics were prepared with powder derived from the sol-gel solution. X-ray diffraction spectra of ceramics and thin films showed a pure BaSnO3 phase with a cubic structure. The effect of sintering temperature was studied to obtain a good crystalline quality of BaSnO3 ceramics. SEM photos were taken both on ceramics and films. An average roughness of 1.8 nm measured by AFM on films clearly indicates the high quality of the film surface. The phase purity and chemical composition were further confirmed by using energy dispersive X-ray spectroscopy. The room temperature dielectric constant (ε′) was found to be ∼17 and 13 at 1 MHz for ceramics and thin films, respectively. Moreover, quite low dielectric loss tangent values were obtained both for ceramics and thin films. The dielectric study in function of temperature showed maximums on the ε’ evolution at 230 °C and 220 °C, for ceramic and thin film, respectively. XRD patterns taken at different temperatures have shown a stable cubic structure of BaSnO3 powder. This structural stability clearly demonstrates that peaks observed on the temperature dependent plots are only related to dielectric phenomena, which have been described. AC conductivity showed an influence of electrically activated charge carriers, both for ceramics and thin films. The present study also signifies that the dielectric properties of BaSnO3 ceramics can be successfully replicated on thin films by a facile and cost-effective deposition method.