Fabrication of two domain Cu2O(0 1 1) films on MgO(0 0 1) by pulsed laser deposition

Single oriented Cu2O(0 1 1) films were fabricated on MgO(0 0 1) substrates at temperature from 450 to 600 °C by pulsed laser deposition. In situ X-ray photoelectron spectroscopy and X-ray induced Auger electron spectroscopy showed that the oxidation state of Cu should be Cu1+. In situ reflection high-energy electron diffraction, ex situ X-ray diffraction and cross-sectional transmission electron microscopy have been used to characterize the structural properties of deposited Cu2O films. The coexistence of two kinds of domains in the Cu2O films was observed. The in-plane orientation relationships for the two kinds of domains are Cu2O[1 0 0]||MgO[1 1 0] and Cu2O[1 0 0]||MgO[1 −1 0], respectively. The formed rotation domains, which perpendicular to each other, can be attributed to the mismatch of rotational symmetry at interface between Cu2O and MgO. The strip-like surface morphology of Cu2O films was investigated by atomic force microscopy and scanning electron microscopy. The band gap of Cu2O films was determined by using the linear extrapolation method.