The optical behaviour of colour centres is studied in thin films of KCI obtained by thermal evaporation onto amorphous substrates. Deposition conditions are optimized in order to minimize chemical and thermal effects on films. Concentration of colour centres even higher than in bulk crystals can be induced by low energy electron irradiation. Thermal bleaching of F centres is observed at room temperature and its kinetics, deduced from absorption measurements, consists of two exponential processes with very different time constants. Luminescence is obtained for the first time from aggregate colour centres in KCl films, and typical emissions of F-2, F-3, F-4 defects (but not of F centres because of concentration quenching) are revealed.
Ercoli, A., Scacco, A., Somma, F., Cremona, M., Montereali, R.m., Martelli, S., et al. (1994). F-AGGREGATE CENTERS IN KCL FILMS. RADIATION EFFECTS AND DEFECTS IN SOLIDS, 132(2), 143-155 [10.1080/10420159408224304].
F-AGGREGATE CENTERS IN KCL FILMS
SOMMA, Fabrizia;
1994-01-01
Abstract
The optical behaviour of colour centres is studied in thin films of KCI obtained by thermal evaporation onto amorphous substrates. Deposition conditions are optimized in order to minimize chemical and thermal effects on films. Concentration of colour centres even higher than in bulk crystals can be induced by low energy electron irradiation. Thermal bleaching of F centres is observed at room temperature and its kinetics, deduced from absorption measurements, consists of two exponential processes with very different time constants. Luminescence is obtained for the first time from aggregate colour centres in KCl films, and typical emissions of F-2, F-3, F-4 defects (but not of F centres because of concentration quenching) are revealed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
