Intrinsic luminescence centers in yttrium–aluminum garnet and yttrium oxide ceramics

Pulsed cathodoluminescence of undoped and ytterbium- and cerium-doped ceramic samples of yttrium–aluminum garnet and yttrium oxide is studied within the range of 220–850 nm in order to clarify the nature of their intrinsic luminescence centers. It is shown that these materials have three types of intrinsic centers, namely, (1) autolocalized excitons with a hole component (О$_{3}^{-2}$) molecular ions associated with cation vacancies) emitting a single band at $\lambda\approx$ 350 nm in yttrium oxide and a double band at $\lambda\approx$ 320 and 350 nm in yttrium–aluminum garnet, (2) $F$ centers emitting a broad band at $\lambda\approx$ 490 nm in yttrium oxide and at $\lambda$ $\approx$ 510 nm in yttrium–aluminum garnet, and (3) Y = O bound radicals emitting a series of narrow bands in the range of 600–730 nm in both materials. It is shown that doping of these materials with ytterbium does not affect the first center characteristics but strongly changes the characteristics of the second and third centers.