Preparation And Properties Of Al-Zr Co-doped ZnO Transparent Conductive Films

ZnO as an important semiconductor material with wide band gap of about 3.3 eV and exciton binding energy of 60 meV is stable in ambient environments. ZnO has good mechanical and electrical coupling performance, fine thermal stability and chemical stability, excellent optical and electro-magnetic properties as well. ZnO has the widespread application prospects such as in gas sensors, piezoelectric devices and solar cell, etc. The ZnO based thin film has enormous application value, especially in the transparent conductive thin film, which has attracted the scientific researchers' attention. The probable mechanism of structure, morphology electronic and optical properties were discussed. The main research content includes:1.The research background of nanomaterials was introduced including the ZnO-based thin film application situation. We introduced preparation and experimental analysis methods of the ZnO-base transparent conductive thin films in this paper.2. We prepared the pure ZnO thin film and sole Al, Zr doping thin film using the radio frequency (RF) magnetron sputtering. The structural, morphological, electrical and optical properties were discussed. The electronic resistivity of the annealed Al doped ZnO and Zr doped ZnO thin film was 6.1×10-2Ω·cm and 0.16Ω·cm, respectively. The transmittance of all the thin films exceeded 80%.3. We prepared the Al-Zr co-doped ZnO thin film using the RF magnetron sputtering and the thin films were annealed at 400℃for an hour. It was obtained that the minimum electronic resistivity achieved 9.93×10-3Ω·m when the deposition time was 30mins after annealed at 400℃for an hour. The average transmittance in the visible range all exceeded 90%. The band gap of the doped ZnO thin films was wider than pure ZnO's and the annealed film's band gap was wider than non-annealed film's due to the Burstein-Moss effect.4. The Al-Zr co-doped ZnO thin films were prepared by RF magnetron sputtering. The formation mechanism of the nanopiece structure on the thin film surface was different from the nanopiece obtained by chemistry method. We speculate the nanopiece structure was formed by nucleation and growth of the small grains from interior of thin film. The annealed ZnO thin films were characterized by various measurements including high resolution transmission electron microscope (HRTEM) and the selected area electron diffraction (SAED) test analysis. It was shown that the sample had good crystallinity. The annealed film's transmittance was lower than non-annealed film's owing to boundary optic scattering. After doping and annealing, the film's band gap was wider.