<title>VUV luminescence of as-grown and electron irradiated corundum single crystals</title>

Abstract

The optical properties of as-grown and electron-irradiated α-Al₂0₃ (corundum) single crystals were investigated at low temperatures, using vacuum-W (VUV) time-resolved luminescence spectroscopy under the synchrotron radiation excitation. It has been shown that in the electron-irradiated crystals the excitation of self-shrunk exciton emission extends to the region of interband transitions. The decay time of the 7.6-eV emission of the self-shrunk excitons in as-grown crystals was found to be about 7 and 23.8 ns respectively for the excitations in the excitonic band and at energies at which several electron-hole pairs are generated. In the irradiated crystals, these lifetimes were by about 2 ns longer than in the as-grown ones. For both crystal states, the nature and dynamics of the electronic excitations are discussed.