Growth and characterization of epitaxial Ba(Co,Zn)1/3Nb2/3O3 thin films

Abstract

Pulsed Laser Deposition has been used to synthesize Ba(Co,Zn)1/3Nb2/3O3 (BCZN) dielectric thin films on MgO (001) substrates. The BCZN films are epitaxial and have an orientation of (001) // MgO (001) and (100) // MgO (100) when deposited at substrate temperatures above 500°C. The film grown at 800°C has the best structural quality, with an X-ray diffraction rocking curve width of ~0.5° and a channeling Rutherford Backscattering Spectrometry χmin value of 8.8%. The surface roughness decreases monotonically with increasing substrate temperature, with a ~3nm root mean square roughness value for the films deposited at 700°C. Optical transmission measurements indicate a strong direct transition at ~4eV and a refractive index of 2.0 in the visible range. A low-frequency dielectric constant of 34 was measured using a planar interdigital contact structure. The resistivity of the film is 3×1010Ωcm at room temperature and has a thermal activation energy of 0.66eV.