THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS THERMO-LUMINESCENCE AND PHOTOLUMINESCENCE STUDIES OF Al2O3 IRRADIATED WITH HEAVY IONS

Thermo-luminescence (TL) spectra of single crystals of Al2O3 (sapphire) irradiated with 200 MeV swift Ag ions at different fluence in the range 1х10 to 1х10 ions/cm has been recorded at room temperature by keeping the warming rate 2K/min. The TL glow curve of the irradiated samples has a simple structure with a prominent peak at ~ 500 K with one small peak at 650 K. The intensity of main peak increases with the ion fluence. This has been attributed to the creation of new traps on irradiation. Also, a shift of 8 K in the peak position towards low temperature side has been observed at higher fluence 1х10 ions/cm. In addition, photoluminescence (PL) spectra of irradiated samples have been recorded at room temperature upon 2.8 eV excitation. A broad band consisting of mainly two emission bands, respectively at 2.5 and 2.3 eV corresponding to F2 and F2 defect centers is observed. The intensity of these bands shows an increasing trend up to fluence 5х10 ions/cm and then decreases at higher fluence 1х10 ions/cm. The results are interpreted in terms of creation of newly defect centers, clustering/aggregation and radiation-induced annihilation of defects.