The effect of annealing on spectra and decay time of X-ray luminescence of zinc oxide powders

The annealing effects on zinc oxide powders have been investigated. Annealing was performed at 800, 1050°C in vacuum and air for 2 h. After that, the powders were annealed in gas mixture consisted of 15% H₂ and 85% Ar for 30 min at 800°C. After vacuum annealing the powders have green luminescence band located at 515 nm and decay time curve of the luminescence has three exponential decays with time constants: 10–50 ns, 100–200 ns, and 1100 ns. After air annealing powders have green luminescence band with peak at 525 nm and decay time curve of the luminescence has three exponential decays with time constants: 5 ns, 100–200 ns, and 4000–5000 ns. Annealing in hydrogenous ambience has no effect on peak position or intensity for powders previously annealed vacuum. In air annealed powders intensity of green luminescence decreases significantly after annealing in hydrogenous ambience.