Growth and Optical Properties of Nonpolar (equation image) Zn1-xCoxO Epitaxial Film on a γ-LiAlO2 Substrate


  • This work was supported by the National Science Council of Taiwan under grant NSC 97-2221-E006-121-MY2.


Nonpolar (equation image) Zn1-xCoxO films are grown on γ-LiAlO2(100) substrates by CVD. X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) results reveal that Co atoms become incorporated into the ZnO film via a substitution for Zn, when x ≤ 0.15. The epitaxial relationships between the nonpolar Zn1-xCoxO film and γ-LiAlO2 substrate are [0001]ZnCoO||[010]LAO and [equation image]ZnCoO||[100]LAO, as determined by TEM. A decrease in the optical band-gap of the nonpolar Zn1-xCoxO film with increasing Co content is observed in absorption measurements.