Two‐stage mechanism of Zn nanoparticles formation in ZnO crystal by Nd:YAG laser radiation

Zn nanoparticles characteristics like size and concentration can be tailored by laser irradiation. A pulsed Nd:YAG laser was operated at a wavelength of 266 nm, pulse duration of 3 ns, and a maximum intensity of 315.0 MW cm−2. Zinc nanoparticles formation is proposed to occur in two stages. In the first stage, Zn interstitials (Zni) are generated at the irradiated site. In the second stage, Zni agglomerate to increase the size of Zn nanoparticles up to 120 nm. Zni formation is implied from an increase in the electrical conductivity, but agglomeration occurs from heat treatment provided by laser irradiation. Single laser pulse irradiation creates small nanoparticles about 7 nm in size. Further laser pulses reduces the concentration of small nanoparticles and increases the size of nanoparticles up to 120 nm. The size and structure was observed by field emission scanning electron microscope and Raman spectroscopy. Topography and electrical conductivity was mapped by atomic force microscopy.