Thickness dependence on structural, dielectric and AC conduction studies of vacuum evaporated Sr doped BaTiO3 thin films

Abstract

Barium titanate (BaTiO3) doped with Strontium (BST) nanoparticles prepared by using wet chemical method were thermally evaporated on to well cleaned glass substrates under the vacuum of 2 × 10−5 Torr, using 12A4 Hind Hivac coating unit. The thickness of the film was measured by quartz crystal monitor. From X-ray analysis, it has been found that BaTiO3 nanoparticles possess tetragonal structure and deposited films has a polycrystalline in nature, whereas the crystallinity of film increases with increase of temperature. Surface morphology of fabricated thin film observed that very homogeneous and uniform size. The transport mechanism in these films under a.c. fields was studied in the frequency range 12 Hz to 100 kHz, at different temperatures (303–483 K). The dependence of dielectric constant and loss factor for different thickness was investigated and results are discussed. The process of a.c. conduction has been explained on the basis of hopping conduction mechanism. The dielectric constant (ɛ′), temperature co-efficient of capacitance (TCC) and temperature co-efficient of permitivity (TCP) were estimated. The dependences of activation energy on thicknesses also studied and reported.