Publication Date:
2011-05-20
Description:
Optical properties have been investigated in titanium doped sapphire, prepared under oxidized condition. Charge-transfer transitions to 3 d states of tetravalent Ti 4+ from 2 p ones of O 2− are found to be located below the fundamental absorption edge of Al 2 O 3 . The photo-excitation for this band leads to the intense blue emission, the spectrum of which is quite different from the luminescence of the d-d transitions in trivalent Ti 3+ . The UV-irradiation also leads to an absorption peak below the charge-transfer band, resulted from that the photo-excited electrons in part form color centers. The post-annealing at higher temperatures above 300°C completely destroys the color centers. The blue photoluminescence is found to be greatly suppressed by the UV-irradiation and is recovered by the post-annealing. This fact indicates that the color centers prevent the blue emission.
Print ISSN:
1757-8981
Electronic ISSN:
1757-899X
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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