The study of structural, dielectric and pyroelectric properties of SBN compositional graded film

Abstract

Strontium barium niobate (Sr1-xBaxNb2O6, SBN) thin films with composition in the range of 0.50<x<0.70 and compositionally graded SBN films have been fabricated by sol-gel method using methoxyethanol as the solvent and pulsed laser deposition (PLD) method. These films were fabricated on platinized-Si(001) wafer, conducting oxides coated lanthanum aluminium oxide (LAO(001)) substrates and niobium doped strontium titanatte (5%Nb-STO(001)) single crystal substrates. These films were potentially used as pyroelectric sensors and integrated optical devices. Their phase structure and crystallinity were characterized by X-ray diffractometer (XRD) using CuaF radiation. The epitaxial properties of SBN films fabricated by PLD were also studied by XRD. The cross-section and surface morphology were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The films fabricated by sol-gel technique had a higher packing density and contained a less aligned orientation as compared to films fabricated by PLD technique. The dielectric properties were measured by impedance analyzer with frequency range 1 kHz to 1MHz. The pyroelectric properties were investigated by a charge integrated with sinusoidal heating method. The leakage currents of SBN either grown on conducting oxides heterojunction grown on LAO or single conducting oxide substrates were measured and compared. The dielectric and pyroelectric properties of SBN compositionally graded films were compared to those measured from single composition films. Correlations between the charges pumping effect and the experimental results were studied.