Oxygen vacancies of zinc oxide were followed by photoluminescence and electron paramagnetic resonance spectroscopies. The green photoluminescence emission was associated with oxygen vacancies: its intensity was enhanced upon static thermal treatment under inert or under vacuum, whereas it decreases upon oxygen treatment. A unique electron paramagnetic resonance signal at g = 1.96 was measured at room temperature after thermal in situ treatment under flow of inert or oxygenated atmospheres, its double integration follows the same trends than the green photoluminescence emission and its evolution was shown to probe the oxygen vacancy concentrations. The relative concentration of the related paramagnetic species would be increased/decreased upon trapping/release of the electron associated to the formation/filling of oxygen vacancy. The influence of Ti impurities on the photoluminescence and RPE signals was investigated. Finally, it was concluded that the electron paramagnetic resonance signal was related to oxygen vacancies and its position shift could be explained by the involvement of some mixing orbitals. Thanks to static (photoluminescence and electron paramagnetic resonance) and dynamic (electron paramagnetic resonance) in situ characterizations, the conditions of formation or filling of oxygen vacancies were considered depending upon the atmosphere and temperature of the pre-treatment of kadox and ex-carbonate zinc oxide. High temperature treatments, inert atmospheres, and vacuum led to the formation of new oxygen vacancies. This process was reversible upon oxygenated atmospheres. The efficiency of such filling up depended upon the temperature and began to prevail on the oxygen vacancy formation below 500K. It was also shown that a few native oxygen vacancies could also be filled.

ZnO Oxygen Vacancies Formation and Filling Followed by in situ Photoluminescence and in situ EPR. Drouilly, C., Krafft, J.M., Averseng, F., Casale, S., Bazer-Bachi, D., Chizallet, C., Lecocq, V., Vezin, H., Lauron-Pernot, H., Costentin, G.: Journal of Physical Chemistry C, 2012, 116[40], 21297-307