Abstract: Zn1-xMgxO thin films were prepared on quartz glass substrates by sol-gel method.The effect of annealing temperature on phase composition,phase segregation and the absorption edge shift in the UV-Vis transmission spectra of high Mg content Zn0.5Mg0.5O thin films was discussed.When the annealing temperature was not more than 500 ℃,Zn0.5 Mg0.5 O film had no phase segregation occurred,and a largest blue shift of the absorption edge of the Zn0.5Mg0.5O thin films annealed at 400 ℃ was observed.Thus,for the Zn0.5Mg0.5O films,annealing temperature is the key factor of affecting the solid solubility of Mg2+ in ZnO,and 400 ℃ is the ideal annealing temperature.Under this condition,the bandgap adjustment of Zn1-xMgxO (x =0-0.8) thin films was studied.With the increase of Mg content,the optical transmission spectra showed that the absorption edge was blue shifted regularitily,and the bandgap tuning from 3.3 eV of pure ZnO to 4.2 eV by varying the Mg content.

Key words: Zn1-xMgxO thin films were prepared on quartz glass substrates by sol-gel method.The effect of annealing temperature on phase composition,phase segregation and the absorption edge shift in the UV-Vis transmission spectra of high Mg content Zn0.5Mg0.5O thin films was discussed.When the annealing temperature was not more than 500 ℃,Zn0.5 Mg0.5 O film had no phase segregation occurred,and a largest blue shift of the absorption edge of the Zn0.5Mg0.5O thin films annealed at 400 ℃ was observed.Thus,for the Zn0.5Mg0.5O films,annealing temperature is the key factor of affecting the solid solubility of Mg2+ in ZnO,and 400 ℃ is the ideal annealing temperature.Under this condition,the bandgap adjustment of Zn1-xMgxO (x =0-0.8) thin films was studied.With the increase of Mg content,the optical transmission spectra showed that the absorption edge was blue shifted regularitily,and the bandgap tuning from 3.3 eV of pure ZnO to 4.2 eV by varying the Mg content.