Growth Mechanisms and Characteristics of ZnO Nanostructures Doped with In and Ga

In this paper we present the crystallization, photoluminescence (PL), and field-emission (FE) properties of ZnO nanostructures doped with In and Ga cationic substituents and grown by the vapor-phase transport process. During the growth, Zn/ZnOx was adsorbed on the surface of Ag nanograins and self-catalyzed to form ZnO nanoparticles. Hexagonal-faced nanobricks and nanorods were grown by increasing the ZnO vapor concentration. However, nanodisks rather than nanobricks were grown when In2O3 was doped. Furthermore, the nanodisks aggregated to form nanoballs when the synthesis was carried out at high In2O3 doping concentrations. In contrast, nanostructures with a sea-urchin-like morphology were grown when Ga2O3 was doped; individual nanorods with a screw-dislocation structure grew from the same root. We present the growth mechanisms for the ZnO, ZnO: In, and ZnO: Ga nanostructures. ZnO: Ga nanorods exhibited better PL intensity and FE properties than ZnO nanorods and ZnO: In nanoballs. (C) 2010 The Japan Society of Applied Physics