Analysis of the band-edge luminescence degradation for ZnO films with Al doping prepared by the sol-gel method

In the study, ZnO, Zn0.95Al0.05O and Mg-doped Zn0.95Al0.05O films were deposited on substrates by the sol-gel technique. X-ray photoelectron spectroscopy, X-ray diffraction, photoluminescence, and conductivity measurements were used to characterize the films. The authors found that the Zn0.95Al0.05O film was 0.56 times the intensity of the band-edge luminescence (BEL) of the ZnO film at room temperature and the Mg-doped Zn0.95Al0.05O film was 1.58 times the BEL intensity of the Zn0.95Al0.05O film at room temperature. According to the experimental results, the authors suggested that the induced reduction of the BEL intensity by Al doping was attributed to an increase in the number of nonradiative recombination defects, a decrease in the nonradiative recombination lifetime, and the enhancement of capacitance variation related to trapping/detrapping of charges.