The thermal physical formation of ZnO nanoparticles and their morphology

The present study examines the structural development of ZnO nanoparticles. The coarse pure Zn powder material was melted and evaporated in an oxygen- filled chamber by renovated hybrid induction and laser heating (HILH) to pr oduce ZnO needle-shaped nanoparticles. Simultaneously, Zn nanoparticles wer e also produced by HILH in an argon-filled chamber. The Zn nanoparticles we re annealed in the atmosphere at temperatures of 300 degrees C, 400 degrees C, 420 degrees C and 500 degrees C, respectively, to investigate the corre sponding thermal oxidation behavior. By annealing above 400 degrees C, Zn s tructural transformation took place, and the morphology of the nanoparticle s changed to needle and/or tetrapod shape. No sintered necks between ZnO na noparticles were found. The growth of the nanoparticles is considered to be controlled by evaporation. (C) 2000 Published by Elsevier Science B.V. All rights reserved.