Point defects in crystalline SiO2: Thermally stimulated luminescence above room temperature

Thermally stimulated luminescence from one natural and two synthetic samples of alpha-quartz has been investigated in the range from room temperature to 400 °C. Comparisons were made between unswept samples and others, taken from adjacent positions in the original stones, that were swept in a hydrogen atmosphere. Three sets of thermally stimulated luminescence (TSL) data were obtained from each sample, corresponding to initial electron irradiation at 77 K, at ice-bath temperature, and a double irradiation at ice bath plus 77 K. Electron spin resonance and infrared absorption data also were obtained from the same samples. A number of TSL peaks were found in the 60–130 °C region and they have been tentatively associated with hydrogen in the crystal. More intense peaks were found in the 200–300 °C region, but only in unswept samples after an ice-bath or ice-bath plus 77-K irradiation. These latter peaks are attributed to electron-hole recombination at [AlO4]0 centers as a result of electron release from alkali-associated electron traps.