Effect of Gallium Concentrations on the Morphologies, Structural and Optical Properties of Ga-Doped ZnO Nanostructures

Abstract

The effect of gallium ion concentrations (0.5 and 2%) on the morphologies, structural and optical properties of Ga-doped ZnO nanostructures are presented. Ga-doped ZnO nanostructures were synthesized on silicon substrates by simple thermal evaporation process using metallic zinc and Ga powders in the presence of oxygen. Interestingly, it was observed that Ga-ions incorporation in ZnO nanomaterials play an important role on the growth kinetics and hence on the morphologies of as-grown Ga-doped ZnO nanostructures. It was seen that at low Ga-concentration, needle-shaped Ga-doped ZnO nanostructures are formed, presumably by subsequent stacking of hexagonal plates. However, when increasing the Ga-concentration, multipods of Ga-doped ZnO were grown. In addition to the morphologies, incorporating Ga-ions into ZnO also affect the room-temperature photoluminescence properties. Therefore, at lower Ga-ion concentration, an intense UV emission was observed while at high Ga-concentration a deep level emission was seen in the room-temperature photoluminescence spectra. This research demonstrates that by controlling the Ga-ion concentration the morphologies and optical properties of ZnO nanomaterials can be tailored.

Defect characterization of low temperature solution grown ZnO

“…Most commonly, Ga 3+ is doped into ZnO to enhance its optoelectronic properties. The doping of Ga 3+ into ZnO has several advantages as the atomic radii of Ga 3+ is similar to that of Zn 2+ , making Ga 3+ highly soluble in ZnO 237. Ga 3+ acts as a donor in ZnO and reduces the electrical resistivity, in turn increasing its electrical conductivity.…”