The effect of annealing Er-doped material, upon the behavior of electrically and optically active defects, was studied. The results showed that the formation of the defects was associated with the interaction of Er atoms or Er-related defects with intrinsic point defects and/or O atoms.

N.A.Sobolev, O.V.Alexandrov, V.V.Emtsev, M.I.Makoviichuk, A.V.Merkulov, E.O.Parshin, D.S.Poloskin, E.I.Shek: Solid State Phenomena, 1996, 47-48, 299-306