Abstract: Tb³⁺-doped Al₂O₃ films on silicon substrates were prepared by the sol-gel method. The Tb³⁺-doped Al₂O₃ films were characterized by differential thermal analysis/thermogravimetric analysis, X-ray diffraction, scanning electron microscope, atomic force microscope and photoluminescence spectra as well. The photoluminescence mechanism of Tb³⁺-doped Al₂O₃ films was analyzed. The effects of heat-treatment temperature and Tb³⁺ ion concentration on the luminescence property of Tb³⁺∶Al₂O₃ films were discussed. The results show that the prepared Al₂O₃∶Tb³⁺ film has high luminescence intensity, the optimum excitation wavelength is 240nm, the optimum concentration of Tb³⁺ dopant is 5mol%, and the main emission is at 544nm under excitation at 240nm. And the prepared Al₂O₃∶Tb³⁺ film has a dense, smooth and crack-free surface texture with a roughness of less than 1.3nm. It is suggested that the film is good enough for fabrication and application of silicon based photoelectronic devices.

Key words: sol-gel, Al₂O₃∶Tb³⁺, film, photoluminescence