The shape of the emission band of the -dopant in oxyfluoride nano-scaled glass-ceramicsV. D. Rodríguez1, V. K. Tikhomirov2, J. Méndez-Ramos1 and A. B. Seddon2
1 Departamento de Física Fundamental y Experimental, Electrónica y Sistemas Universidad de La Laguna - 38206 La Laguna, Tenerife, Spain
2 Novel Photonic Glasses Research Group, Center for Advanced Materials University of Nottingham - Nottingham NG7 2RD, UK
received 30 July 2004; accepted 2 November 2004
published online 10 December 2004
We propose a diagram showing the sequence of Stark-split energy levels for the 4I15/2 and 4I13/2 states of doped into oxyfluoride, nano-scaled glass-ceramics based on low- and room temperature measurements of respective emission and absorption bands. The room temperature broadest and flattest 1.55 telecommunications emission band of to date reported earlier for such glass-ceramics is interpreted using this framework. By investigating the low-temperature behaviour, we show that the shape of the 1.55 band at room temperature is mostly due to thermal population of higher Stark sublevels in the excited 4I13/2 state. Two sites for are proposed which relate, respectively, to the glassy and nano-crystalline phases of the glass-ceramics and their relative contributions to the emission spectrum are identified. The -site in the nano-crystalline phase is shown to be cubic with nearby charge compensation by one interstitial , without appreciable clustering of ions.
81.05.Pj - Glass-based composites, vitroceramics.
61.46.+w - Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals.
© EDP Sciences 2005