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

摘要

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/ZnO_x 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 ln_2O_3 was doped. Furthermore, the nanodisks aggregated to form nanoballs when the synthesis was carried out at high ln_2O_3 doping concentrations. In contrast, nanostructures with a sea-urchin-like morphology were grown when Ga_2O_3 was doped; individual nanorods with a screw-dislocation structure grew from the same root. We present the growth mechanisms for the ZnO, ZnO:ln, and ZnO:Ga nanostructures. ZnO:Ga nanorods exhibited better PL intensity and FE properties than ZnO nanorods and ZnO;ln nanoballs.