Facile, seedless and surfactant-free synthesis of ZnO nanostructures by wet chemical bath method and their characterization

Abstract

In the present work, we report on the synthesis of ZnO nanostructures by a facile, surfactant-free and seedless growth by wet chemical route. The reported route is simplistic and versatile as by only varying the reaction time we were able to synthesize ZnO nanostructures of various morphologies such as pure sheets, rod-embedded sheets, pure rods and petal-shaped rods. A possible mechanism for the formation of ZnO sheets and its transformation to rods shaped morphology has been put forward. In the present study, we have carried out the structural, optical, photoelectrochemical and electronic properties only for the ZnO nanorods. The as-synthesized ZnO nanorods with wurtzite crystal structure exhibit high crystallinity with mean size of 1.28 µm × 287 nm. The nanorods exhibit a strong near-band edge emission at 388 nm which indicates the presence of shallow nitrogen acceptor defects in ZnO. The n-type conductivity of the nanorods was further confirmed by photoelectrochemical (PEC) and scanning tunneling spectroscopy studies. The synthesized ZnO nanorods exhibited PEC properties due to the reduced oxygen-related defects. The scanning tunneling spectroscopy measurements revealed a little shrink in the bandgap due to the nitrogen doping which was in good agreement with the emission spectroscopy results.