Influence of post deposition annealing process on the optical and microwave dielectric properties of Bi < inf > 1.5 < /inf > Zn < inf > 1.0 < /inf > Nb < inf > 1.5 < /inf > O < inf > 7 < /inf > thin films

Abstract

Thin films of Bi1.5Zn1.0Nb1.5O7 (c-BZN) were deposited at ambient temperature on fused silica substrates by pulsed laser deposition (PLD) followed by a post deposition annealing at a temperature between 200-800°C. The post deposition annealing resulted in the formation of crystalline c-BZN thin films from the as deposited amorphous thin films. For the films that are annealed at 500°C, diffraction peaks are found to be appearing. The grain size and surface roughness of the films are found to be increasing with the increase in annealing temperature. The band edge of the as deposited c-BZN thin films are about 3.6 eV. There is a gradual increase of the optical band gap of c-BZN thin films with the annealing temperature. The as-deposited films and the films annealed up to 300°C shows a lower value of dielectric permittivity and loss tangent. There is a sudden increase of dielectric permittivity and loss tangent for the films annealed at 400°C and above. The dielectric permittivity was decreasing slightly for the films annealed above 700°C. Copyright © Taylor & Francis Group, LLC.