Phase dependent TL-OSL studies in various phases of chemically synthesized Cu doped crystalline SiO2

Cu doped crystalline SiO2 in various phases viz. coesite, pyrite, and cristobalite has been successfully synthesized through the chemical route. All the studied samples show mixed phases and the relative contribution is found to be dependent on the annealing temperature. For sample heated at 300 °C the most dominant phase is Coesite whereas for samples heated in the temperature range 500-900 °C the dominant phase is pyrite along with the quartz, coesite and cristobalite phase. The Cu+ emission intensity as well as wavelength in all these samples is found to be dependent on the dominant phase as well as relative contribution of other less dominant phases. For sample heated at 300 °C in which dominant phase is coesite the emission is observed around 360 nm. The samples which are heated in the temperature range 500-900 °C in which dominant phase is pyrite shows double humped emission with peaks around 360 nm and at 395 nm. The study shows that cristobalite phase is detrimental to Cu+ luminescence. Samples in which cristobalite phase is present in large amount, less intense Cu+ luminescence is observed. The TL/OSL also follows the similar trend. Of the several samples, maximum TL/OSL sensitivity is obtained for the 700 °C heated sample for which the relative contribution of cristobalite phase is minimum. On the basis of an area integration method; integrated over initial 3 s, the OSL sensitivity in this sample is found to be 2.3 times the sensitivity of commercial Al2O3:C.