Optical, electrical and infrared emissing properties of DC magnetron sputtered ZnO:Al thin films
Wang Wenwen Diao Xungang Wang Zheng Wang Tianmin (School of Science, Beijing University of Aeronautics and Astronautics, Beijing 100083, China)
Aluminium-doped zinc oxide (ZnO:Al) films were deposited on glass substrate by DC reactive magnetron sputtering from a Zn-Al metallic target (ω(Al)=3%). Films with novel, tangly string-like surface morphology, an average optical transmittance up to 90% in the visible range, a widest band gap of 3.47?eV and electrical resistivity down to 1.80×10 -6 ?Ω·m were obtained. The infrared emissivity in 8～14?μm waveband is distributed in the range of 0.26～0.9. The surface morphology, crystallinity, infrared emissivity as well as the electrical and optical properties of the samples were characterized using X-ray diffraction, scanning electron microscopy, spectrophotometry, infrared radiometer and Hall-effect measurement. The optical, electrical and infrared emissing properties of the films depend on substrate temperature and sputtering power obviously and regularly. The relationship between sheet resistance and infrared emissivity of ZnO:Al(ZAO) thin films follows a quadratic function as the sheet resistance is below 45?Ω.