Influence of Post Deposition Annealing Process on the Optical and Microwave Dielectric Properties of Bi_(1.5)Zn_(1.0)Nb_(1.5)O_7 Thin Films

摘要

Thin films of Bi 5Zn_(1.0)Nb_(1.5)O_7(c-BZN) were deposited at ambient temperature onfused silica substrates by pulsed laser deposition (PLD) followed by a post depositionannealing at a temperature between 200-800℃. The post deposition annealing resultedin the formation of crystalline c-BZN thin films from the as deposited amorphous thinfilms. For the films that are annealed at 500℃, diffraction peaks are found to beappearing. The grain size and surface roughness of the films are found to be increasingwith the increase in annealing temperature. The band edge of the as deposited'c-BZNthin films are about 3.6 eV. There is a gradual increase of the optical band gap of c-BZNthin films with the annealing temperature. The as-deposited films and the films annealedup to 300℃ shows a lower value of dielectric permittivity and loss tangent. Thereis a sudden increase of dielectric permittivity and loss tangent for the films annealedat 400℃ and above. The dielectric permittivity was decreasing slightly for the filmsannealed above 700℃.