title: Strong temperature-dependent crystallization, phase transition, optical and electrical characteristics of p-type CuAlO2 thin films.
abstract: We report here a reliable and reproducible single-step (without post-annealing) fabrication of phase-pure p-type rhombohedral CuAlO2 (r-CuAlO2) thin films by reactive magnetron sputtering. The dependence of crystallinity and phase compositions of the films on the growth temperature was investigated, revealing that highly-crystallized r-CuAlO2 thin films could be in situ grown in a narrow temperature window of ∼940 °C. Optical and electrical property studies demonstrate that (i) the films are transparent in the visible light region, and the bandgaps of the films increased to ∼3.86 eV with the improvement of crystallinity; (ii) the conductance increased by four orders of magnitude as the film was evolved from the amorphous-like to crystalline structure. The predominant role of crystallinity in determining CuAlO2 film properties was demonstrated to be due to the heavy anisotropic characteristics of the O 2p-Cu 3d hybridized valence orbitals.
authors.affiliation: School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, P.R. China. zqyao@zzu.edu.cn.
authors.forename: Suilin
authors.initials: S
authors.lastname: Liu
authors.forename: Zhiheng
authors.initials: Z
authors.lastname: Wu
authors.forename: Yake
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Yao
authors.forename: Jiajie
authors.initials: J
authors.lastname: Fan
authors.forename: Yiqiang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Junhua
authors.initials: J
authors.lastname: Hu
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Guosheng
authors.initials: G
authors.lastname: Shao