Cathodoluminescence of synthetic quartz

Cathodoluminescence from undoped and Ge-doped high-purity synthetic quartz is examined over the temperature range 40 to 300 K. The undoped quartz exhibits the well known blue ( approximately 470 nm) luminescence attributed to the decay of self-trapped excitons. Ge-doped quartz shows green ( approximately 570 nm) luminescence at low temperatures; it is proposed that this emission occurs as a result of exciton self-trapping occurring at Ge substitutional sites. Line features which are considered as resulting from molecular oxygen ions are observed in both undoped and doped material. Evidence is presented that emission at 380 nm relates to an impurity incorporated during growth.