Growth Mechanism of Hollow ZnO Microsphere with Aperture Prepared by Oxidation of Zn Powder

Abstract

ZnO microsphere with aperture were synthesized using pure Zn powder as templates via thermal evaporation methods. X-ray diffraction pattern shows the change of crystal structures from Zn to ZnO. SEM and TEM images show that the samples prepared at low gas pressure have hollow ZnO microsphere with aperture. Compared with the morphologies of samples synthesized at high gas pressure, the growth mechanism of hollow ZnO microsphere with aperture is presumed in detail. The experimental results indicate that the evaporation of Zn inside the ZnO microsphere shell prompts the formation of hollow microsphere, and that the high pressure induces the breakage of weak locations to form the apertures, which eventually results in the appearance of ZnO microsphere with small pores and big apertures.