Role of [AlO4]0centers in the 380-nm thermoluminescence of quartz

Abstract

Spectrally resolved thermostimulated-luminescence (TSL) measurements have been carried out on samples of synthetic quartz, submitted to different treatments in order to change the type of charge compensation at the substitutional aluminum sites. Near-infrared (NIR) optical absorption, electron paramagnetic resonance (EPR), and ac ionic conductivity measurements have been performed to monitor the kinetics of defects involved in the treatments. A specific treatment, consisting in a prolonged high-temperature annealing of the samples in vacuum (10 h at 1400 ${}_{}{}^{\mathrm{°}}{}_{}{}^{}\mathrm{C}$, 1 Pa), is shown to reduce the presence of ionic charge compensators at the Al sites and, at the same time, to induce an intense 380-nm TSL, undetected before the treatment. The assignment of the 380-nm emisson to [${\mathrm{AlO}}_4$ ${]}^0$ centers is proposed and is seen to be in good agreement with a number of experimental results presented so far.