Flash synthesis of flower-like ZnO nanostructures by microwave-induced combustion process

Flower-like ZnO particles were fabricated from zinc nitrate and urea via the microwave-induced combustion technique (MICT). The structure and morphology of the products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). The effects of growth conditions such as microwave power, radiation time, and molar ratio of urea/Zn²⁺ were investigated. Results show that the morphologies and particle sizes of the final products depend on the molar ratio of urea/Zn²⁺. The SEM images of ZnO flowers grown in different periods were employed to explain the formation mechanism. This study provides a simple and efficient approach for synthesizing flower-like ZnO heterostructures.