RETRACTED: Growth of center-oriented filamentous microstructures on the surface of ZnO–Co3O4 targets under pulsed laser radiation

Abstract

Abstract This paper presents the results of the study of the composition, structure and morphology of ZnO–Co3O4 ceramic targets before and after laser ablation by the KrF excimer laser. X-ray diffraction analysis showed that the composition of the targets changes under the thermal effects of laser radiation: a new phase of CoO of the cubic structure is formed (a = 4.25 A). The radial distribution of elements in the ZnO–Co3O4 targets after ablation by the KrF excimer laser was discovered for the first time. The atomic concentration of cobalt in the center was determined to be several times higher than its concentration at the edge of the targets. This can be explained by the thermal model of laser-semiconductor interaction. The morphology of the targets surface after the laser ablation was discovered to undergo significant changes. Pulsed nanosecond laser radiation induces the formation of center-oriented cone-shaped structures and micro-whiskers on the target surface. It was determined that the higher is the concentration of doping impurities in the target, the greater is the number of structures observed on the surface. The formation of “cones” and microwhiskers is explained by the generalized growth model of the vapor–liquid–crystal mechanism.