Photoluminescence characteristics of undoped and terbium chloride doped zinc oxide films deposited by spray pyrolysis

The photoluminescence characteristics of undoped and TbCl3-doped zinc oxide films deposited by the spray pyrolysis technique are reported. Undoped films present the characteristic blue-green emission peak at ∼508 nm observed in single-crystal and powder ZnO. The TbCl3-doped films present a luminescence peak at ∼540 nm. The light emission of the doped films decreases with time of exposure of the sample to the excitation light. The phenomenon is interpreted in terms of a simple model in which a competitive process of hole trapping and phototrapping occurs at a radiative recombination center generated by the TbCl3.