Controllable synthesis and characterization of hollow-opened ZnO/Zn and solid Zn/ZnO single crystal microspheres

摘要

We report the growth and structural properties of hollow-opened ZnO/Zn and solid Zn/ZnO single crystal microspheres on a silicon (111) substrate. The microspheres were synthesized from ZnO mixed with Zn by chemical vapour deposition. The ZnO/Zn microspheres exhibit a hollow interior and a spherical shell with a partly opened mouth along the c-axis of the hexagonal wurtzite ZnO structure oriented vertically to the substrate. The Zn/ZnO microspheres are solid. The microsphere growth process includes the deposition of Zn and ZnO particles followed by the evaporation of Zn from the breaking shell of the ZnO microparticles. The break in the shell is caused by the evaporation of Zn. The morphologies, chemical composition and crystal structure of the microspheres were characterized using x-ray diffraction, energy dispersive x-ray spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy. The room-temperature photoluminescence spectra were investigated using a 325 nm He-Cd laser as the excitation source.