Investigation of the structural, optical and dielectric properties of highly (1 0 0)-oriented (Pb0.60Ca0.20Sr0.20)TiO3 thin films on LaNiO3 bottom electrode

Highly (1 0 0)-oriented Pb0.60Ca0.20Sr0.20TiO3/LNO/LAO structure was fabricated using a chemical deposition process via spin-coating technique. XRD revealed that both LNO and Pb0.60Ca0.20Sr0.20TiO3 films grown on LAO(1 0 0) substrate and LNO/LAO(1 0 0) structure were crystallized to be highly (h 0 0)-oriented, respectively. AFM images revealed smooth surfaces, spherical-shaped grains and a crack-free surface with a roughness of about 3–7 nm. The tetragonal perovskite phase was confirmed by Raman spectroscopy for Pb0.60Ca0.20Sr0.20TiO3/LNO/LAO and Pb0.60Ca0.20Sr0.20TiO3/LAO structures. The optical transmittance of 340 nm thick Pb0.60Ca0.20Sr0.20TiO3 films on a LAO(1 0 0) substrate exhibited an average transmittance above 80% in the wavelength range of 500–1000 nm and an optical band gap Eg of 3.56 and 2.87 eV for the direct and indirect transition processes, respectively. The Au/Pb0.60Ca0.20Sr0.20TiO3/LNO/LAO structure has a hysteresis loop with remnant polarization, Pr, of 12 μC/cm2, and a coercive field, Ec, of 46 kV/cm for an electric field at 370 kV/cm along with a dielectric constant over 1200.