Luminescence quantum yield and multiplication of electronic excitations in the corundum crystals
Yerevan Physics Institute, Alikhanian Br. 2, 375036, Yerevan, Armenia
2 Lebedev Physics Institute, Leninski prosp. 53, 117924, Moscow, Russia
Revised: 20 January 1999
Published online: 15 November 1999
The excitation spectra of luminescence in irradiated and nonirradiated corundum crystals are investigated by means of highly polarised synchrotron radiation in 5 to 30 eV region. In the fundamental absorption region the double-exciton peaks are observed in the region 8.5-9.2 eV for irradiated (especially by neutrons) crystals at temperature 90 K. At 9.5 eV sharp drops appeared, in the luminescence spectrum space which were interpreted as nonirradiative near-surface recombination, the probability of which sharply increased at high absorption coefficients. The enhancement of the luminescence efficiency in the high-energy region was connected with the decay effect of electron excitations as well as with the influence of volumetric excitations leading to the enhancement of recombination glow.
PACS: 61.72.-y – Defects and impurities in crystals; microstructure / 61.80.-x – Physical radiation effects, radiation damage / 74.62.Dh – Effects of crystal defects, doping and substitution
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999