Frequency response of microwave dielectric Bi2(Zn1/3Nb2/3)2O7 thin films laser deposited on indium-tin oxide coated glass

Bi-2(Zn1/3Nb2/3)(2)O-7 (BZN) thin films were prepared by using a pulsed laser deposition technique. For films in situ deposited on indium-tin oxide (ITO) coated glass substrates, the crystalline phase can be obtained by growing at a substrate temperature (T-s) higher than 475 degrees C. Too low a substrate temperature (T-s< 400 degrees C) results in the amorphous phase, whereas too high a temperature (T-s> 600 degrees C) leads to substantial interaction between the BZN film and the ITO layer. For the films deposited at a 500 degrees C substrate temperature, the texture characteristics change with their thickness. The films are (222) preferentially oriented when they are thin, and (400) preferentially oriented when they are thick. The optical properties, measured using optical spectroscopy, reveal that the index of refraction (n) and absorption coefficient (kappa) vary between n=2.08-2.51 and kappa=1.22x10(-5)-1.88x10(-4) nm(-1), respectively. These optical parameters do not change significantly with the preferred orientation and thickness of the films. However, the low frequency dielectric properties are closely correlated with the material's characteristics. The crystalline BZN films have a markedly larger dielectric constant than the amorphous films. (C) 2000 American Institute of Physics. [S0021-8979(00)09801-7].