Laser assisted preparation of doped ZnO nanocrystals

Preparation of doped ZnO nanoparticles (NPs) represents a challenging task due to the tendency of self-compensation of the introduced defects by the intrinsic ones. One of the possible ways of achieving reliable p-doping in ZnO is dual acceptor doping, i.e. simultaneous introduction of two types of acceptors. In the present paper the capabilities of laser ablation and post-irradiation processes for preparation of N-doped and Ag-, N-co-doped ZnO NPs were investigated. In order to obtain doped ZnO NPs, Nd:YAG laser ablation of Zn in ammonium nitrate (NH₄NO₃) solution and sequential laser ablation of Ag and Zn in ammonium nitrate solution were used. The composition, structure and morphology of the prepared NPs were controlled through an additional treatment of the colloids by the second harmonic of the Nd:YAG laser. The influence of the ablation processes sequence and additional laser irradiation parameters on the morphology, structural, optical characteristics and chemical composition of the synthesized NPs was examined. The results obtained reveal that the doping takes place after laser ablation of zinc in ammonium nitrate and silver target in the ZnO colloid in NH₄NO₃ solution that was confirmed by X-ray photoelectron spectroscopy analysis indicating the substitution of N at O site.