Large-scale fabrication of ZnO micro-and nano-structures by microwave thermal evaporation deposition

A novel thermal evaporation-deposition approach using microwave energy was employed for the fabrication of ZnO micro-and nano-structures. Batch fabrication of ZnO structures including microtubes, microrods, nanowires and nanobelts were successfully obtained with a unique source materials-substrate configuration in achieving desirable temperature profile. Zinc or zinc oxide source materials are evaporating from the high-temperature zone in an enclosure and single crystalline nano-or micro-structures are grown on the substrate materials with controllable dimensions by using appropriate processing conditions. Substrate, temperature, and catalyst showed significant impacts on the controlled growth of the ZnO nano- and micro-structures. X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterizations reveal that these products are pure, structurally uniform, and single crystalline. The photoluminescence (PL) exhibits strong ultraviolet emission at room temperature, indicating potential applications for short-wave light-emitting photonic devices.