Effect of Al2O3-doping on the structure and optoelectronic characteristics of MgZnO thin film prepared by RF magnetron sputtering

A systematic study of the effect of Al2O3 doping concentration in targets on the structure and optoelectronic characteristics of sputtered MgZnO films was conducted. The films were prepared on glass substrates by radio frequency magnetron sputtering from a MgZnO target mixed with 0–4 wt.% Al2O3. X-ray diffraction analysis demonstrated that the Al-doped MgZnO films had a highly (002) preferred orientation with only one intense diffraction peak. The electrical properties of the Al-doped MgZnO films were dependent on the Al2O3 concentration. Optimal results of Al-doped MgZnO films were obtained at an Al2O3-doping concentration of 2 wt.%, with low resistivity of 2.82 × 10−3 Ω-cm and high transmittance of 91% in the visible region. Outstanding electrical properties were achieved because of the significantly increased carrier concentration. The optical bandgap of the Al-doped MgZnO films showed a short-wavelength shift with increased Al2O3-doping concentration. The low electrical resistivity and high transparency of Al-doped MgZnO films indicated their potential as transparent conductive oxide window materials for UV optoelectronic devices.