Site location and optical properties of Eu implanted sapphire

Synthetic colourless transparent (0001) sapphire crystals were implanted at room temperature with 100 keV europiurn ions to fluences up to 1 x 10(16) cm(-2). Surface damage is observed at low fluences, as seen by Rutherford backscattering spectrometry under channelling conditions. Optical absorption measurements revealed a variety of structures, most probably related to F-type defects characteristic of implantation damage. Thermal treatments in air or in vacuum up to 1000 degrees C do not produce noticeable changes both in the matrix or the europium profiles. However, the complete recovery of the implantation damage and some redistribution of the europium ions is achieved after annealing at 1300 degrees C in air. Detailed lattice site location studies performed for various axial directions allowed to assess the damage recovery and the incorporation of the Eu ions into well defined crystallographic sites, possibly in an oxide phase also inferred from optical absorption measurements. (c) 2005 Elsevier B.V. All rights reserved.