Defects engineering of α-Al 2 O 3 via high-temperature annealing and Ti ion implantation for enhanced luminescence and thermometric applications

Aluminum oxide (Al 2 O 3 ) has garnered considerable interest owing to its defect characteristics, superior optoelectronic, and mechanical properties, enabling broad application prospects in chemical, sensing, and related technologies. Oxygen vacancies (F and F + center), as prevalent defects in Al 2 O 3 , have attracted considerable research attention due to their promising application prospects. In this study, oxygen vacancies and their aggregates (F 2 and F 2 2+ ) were efficiently and conveniently fabricated in Al 2 O 3 via high-temperature (1450 ∘ C) annealing under N 2 atmosphere. Subsequent low-energy and low-dose Ti ion implantation effectively sensitized the F 2 2+ luminescence, enhancing the fluorescence intensity by an order of magnitude. Temperature-dependent studies revealed that elevated temperatures attenuated the sensitization effect, resulting in progressive fluorescence quenching. Concurrently, spectral broadening (increased FWHM) accompanied a blueshift of the emission peaks. This synergistic thermal response suggests promising potential for thermometry applications.