Characteristics of aerosol deposition-fabricated (Ba0.6,Sr0.4)TiO3 thick films

The aerosol deposition (AD) technique is unique among today??s film growing technologies because ceramic thick films can be fabricated at room temperature. Thick (Ba0.6,Sr0.4)TiO3 films have been fabricated on Si/SiO2/Ti/Pt substrates by AD method. As-deposited films and films postannealed at different temperatures have been investigated by SEM, XRD, XPS, UV-PYS and impedance spectroscopy. UV-PYS measurements showed that Fermi level is found closer to the valence band when postannealing temperature has been increased, suggesting that the films are acting more strongly like a p-type semiconductor as postannealing temperature increases. Leakage currents have been found to increase with increase in postannealing temperature and it is believed that this effect is caused by increase in the conductance of grain boundary as revealed by impedance spectroscopy measurements. A secondary phase is observed in XRD patterns of the samples annealed at temperatures of 7000C or above. The decrease in grain boundary resistance observed by impedance spectroscopy measurements with increase of annealing temperature is explained by a reduced potential barrier at the grain-grain boundary interface by annealing.