TL is the heat stimulated emission from a material, being exposed to an ionizing radiation prior to thermal treatment 21. TL studies can help in locating the trap states and their nature in semiconducting crystal systems 17, 18, 19, 20. However, in order to understand the defect levels and their nature in a material, it must be studied rigorously, which can be brought about by TL study. Most of the work has been reported on photoluminescence of undoped as well as doped ZnAl 2O 4 8, 9, 10, 12, 13, 14, 15, 16. Due to complex crystal structure and multiple defect centers such as cationic-anionic vacancies, antisite defects and cationic interstitial, it shows alluring luminescence 6, 7, 8, 9. It is a n-type semiconducting material, its conductivity prominently attributed to Al Zn antisite defects which is a shallow defect near conduction band edge accompanied by cationic vacancies 12. It is a wide band gap material with band gap value of ~3.8 eV in bulk form 11. It crystallizes in fcc crystal system with Fd \(\bar\) m space group. Zinc aluminate (ZnAl 2O 4) is a well known member of spinel family possessing versatile properties and magnificent applications 5, 6, 7, 8, 9, 10. Metal oxides are drawing considerable attention owing to their non-toxic nature and tunable luminescence properties attributable to the defect states. In the search of better and efficient luminescent material for commercial applications, scientific community has been continuously exploring photoluminescence (PL) and thermoluminescence (TL) in different materials 1, 2, 3, 4. All results when summed up, predict ZnAl 2O 4 to be a quality material for dosimetry. X-ray photoelectron spectroscopy indicated the presence of various types of defects specifically Al Zn antisite defect, oxygen and zinc vacancies which are further upheld by photoluminescence and Raman spectroscopy. The mechanism of trapping, retrapping and recombination have been depicted through schematic band model diagram. Shallow and deep traps are observed in crystals attributed to O − vacancies and F centers. Different type of fuels employed in combustion synthesis show a remarkable effect on the trap distribution and hence luminescence properties. Excellent TL response is observed from γ- and ultraviolet-irradiated samples at different doses and exposure durations, respectively. To understand the nature and distribution of defects in its crystal lattice, thermoluminescence (TL) study has been carried out. Defect states in ZnAl 2O 4 have a significant role in its applicability as a luminescent material.
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