Charge Compensation of Er3+ Ions in Ca1—xErxF2+x Thin Films at Low Rare-Earth Substitution Rates
✍ Scribed by Césaire, T. ;Hirsch, L. ;Barrière, A. S. ;Bouffard, M. ;Jouart, J. P.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 201 KB
- Volume
- 168
- Category
- Article
- ISSN
- 0031-8965
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✦ Synopsis
The Er 3 ions in Ca 1Àx Er x F 2x (x 0X01) thin layers grown by sublimation on Si substrates were selectively excited using a laser-induced up-conversion technique under focused excitation at liquid nitrogen temperature. By comparison with the results previously published on bulk crystals, two (Er 3 , F À i ) centers of tetragonal and trigonal symmetry and one (Er 3 , O 2À ) center of trigonal symmetry were identified in these films. These centers exhibit noticeable green luminescence when the laser wavenumber is tuned on the excited-state transition 4 I 13a2 3 4 F 5a2 of each one of them. The emitting 4 S 3a2 level is populated through a two-step absorption process. A comparison of photoluminescence spectra of thin films and bulk crystals testifies to a lower density of aggregated centers in the films. T. Ce Âsaire et al.: Charge Compensation of Er 3 Ions in Ca 1Àx Er x F 2x Thin Films