LUMINESCENCE OF RUTILE-LIKE GEO2 CRYSTALS

Thermoluminescence glow peaks and emission spectra data are reported f or undoped and Al doped GeO2 tetragonal crystals over the temperature range from 45 to 700 K. For the pure crystal the emission peaks near 4 75 nm below 150 K but at higher temperatures it is characterised by re d emission near 720 nm. For samples irradiated at room temperature the Al: GeO2 shows 575 nm emission below 75-degrees-C but primarily red s ignals at higher temperature. Separation and activation energies of co mponent glow peaks are recorded. The thermoluminescence spectra alter after repeated irradiation and measurement. Further, comparisons are m ade between the thermoluminescence spectra and those obtained during X -ray or electron beam irradiation. The cathodoluminescence spectra dif fer at 300 K with a dominant 575 nm peak for the Al: GeO2 and bands ne ar 300, 400, 540, 575 and 720 nm for the pure sample. Below room tempe rature there are significant differences although both show extra band s near 75 to 100 K peaked at 310 and 370 nm. Models of the role of the Al impurity are discussed.