Annealing Temperature-Dependent Structural, Optical, and Electrical Properties of [(Ba1−zCaz)(Zr0.1Ti0.9)O3], (z = 0.155), Films

Abstract

Thin films were deposited, on quartz and p-Si (100) substrates, by radio frequency (RF) sputtering of ceramic barium calcium zirconate titanate [(Ba1−zCaz)(Zr0.1Ti0.9)O3], (z = 0.155), target. The as-deposited films were annealed for one hour at different temperatures, between 500 °C and 800 °C. The occurrence of film crystallization was observed on annealing at and above 600 °C. However, films peeled out on annealing at 800 °C. The structure, optical transmittance, dielectric constant and leakage current of the prepared films (hereafter referred to as BCZT0.9 films), annealed at different temperatures, were measured. Refractive index and optical bandgap were obtained from the measured optical transmittance of the films deposited on quartz substrates and annealed at different temperatures. The optical bandgap of the BCZT0.9 films was found to reduce from 4.24 to 3.87 eV with the increase in annealing temperature. On crystallization, the leakage current density of the prepared films decreased by order of 3, from ∼10−6 for amorphous to ∼10−9 A cm−2 for crystalline films. The current-voltage variations of the prepared films exhibit different conductions for different annealing treatments. The dielectric constant was obtained maximum, 148 (at 1 MHz), and leakage current density minimum, 3.6 × 10−9 A cm−2 (at 3.0 × 102 kV cm−1 electric field), for the films annealed at 750 °C. Electrical properties were observed to improve for the films annealed at 750 °C than other annealed films.