Luminescence and colour centres in Al2O3:Si,Ti

Role of Ti4+ in the luminescence process of Al2O3:Si,Ti

“…Their PSTL measurements reveal that a band at 5.4 eV stimulates the 420 nm emission in this material. This excitation band was erroneously identified as F-center by Mehta and Sengupta [4], as was also pointed out by McKeever et al [3]. According to Mehta and Sengupta [4], Ti ion in the Al 2 O 3 lattice is expected to present as substitutional Ti 3 + ion.…”

“…Out of these, TL peak at 250 1C was observed to be most intense having a detection threshold of 0.258 mC kg À 1 . Various dosimetric characteristics of this TL phosphor have been investigated and reported by Mehta and Sengupta [1,2,4]. Bhatt et al [5,6] have recently reported TL and OSL studies on Al 2 O 3 :Si,Ti phosphor.…”

“…Mehta and Sengupta [4] observed that the PL excitation spectrum, excitation spectrum of photostimulated thermoluminescence (PSTL) and the reflectance spectrum of Al 2 O 3 :Si,Ti show the presence of 225 nm band in the lattice. They have also concluded that the Ti impurity is necessary along with Si for obtaining a pronounced 225 nm band.…”

“…Mehta and Sengupta [4], from their photostimulated thermoluminescence (PSTL) studies have shown that TL traps in Al 2 O 3 :Si,Ti phosphor consist of trapped electron centers created by the action of Si impurity at 2000 1C during the phosphor preparation in air. Mehta and Sengupta [4] observed that the PL excitation spectrum, excitation spectrum of photostimulated thermoluminescence (PSTL) and the reflectance spectrum of Al 2 O 3 :Si,Ti show the presence of 225 nm band in the lattice.…”

The role of the synthesis route to obtain densified TiO2-doped alumina ceramics

“…3 TiO 2 -doped alumina is also interesting because of its electronic 4 and optical applications. 5 On the other hand, it is well known that the addition of a small amount of certain additives, such as TiO 2 , to ␣-Al 2 O 3 , considerably changes its sintering behaviour to manufacture dense materials. 6 The typical bimodal sintered microstructure of the monolithic material contained ␣-alumina platelets in an equiaxed matrix is dramatically changed when different dopants are added, showing a mixed microstructure composed by anisotropic grains embedded in the original equiaxial matrix.…”