Photoluminescence of ZnO ceramics sintered with a flux

ZnO ceramics both with and without boric acid as a flux were sintered at T S = 800 – 1200 ∘ C and their luminescent characteristics were compared. In obtained samples UV as well as visible emission bands were observed. The addition of the flux was shown to cause the increase of grain size and the improvement of crystalline quality of the ceramics, which was ascribed to the creation of a liquid phase during the sintering process. It was found that the adding of 1 wt% of boric acid to ZnO powder allowed ceramics preparation without any pressing of the starting materials, in this case T S = 950 ∘ C being enough to obtain firm and dense ceramics. This ceramics had higher intensity of UV emission and lower intensity of visible emission than ceramics sintered without the flux.