Luminescence of impurity-bound excitons in corundum

Autor: B. R. Namozov, V. A. Vetrov, R. I. Zakharchenya, S. M. Muradov
Rok vydání: 2002
Předmět:
Zdroj: Physics of the Solid State. 44:1459-1462
ISSN: 1090-6460
1063-7834
DOI: 10.1134/1.1501337
Popis: The luminescence characteristics of M3+: Al2O3 crystals, where M3+ stands for an isoelectronic cation impurity with a filled electron shell, namely, Sc3+, Y3+, or La3+, were studied. The luminescence of excitons bound (BE) to these impurities was detected. The position of the BE energy states at the long-wavelength absorption edge as a function of the M3+ ionic radius was established. The energies of the long-wavelength BE creation threshold and of the maximum of the BE luminescence band were approximated empirically by third-order polynomials of the Toyozawa polynomial type, which describes electron-phonon interaction. The energy and spatial structure of the BE was found to be similar to that of a self-trapped exciton (STE). The BE and STE states are separated by an energy barrier, and energy transfer from the STE to BE is frozen at low temperatures.
Databáze: OpenAIRE