Surfactant-free fabrication of ZnO spheres and pseudospherical structures

ZnO spheres and pseudospherical structures have been synthesized by a surfactant-free wet chemical method. The products were formed by a dissolution/reprecipitation mechanism. Room temperature ferromagnetism has been observed in the products, which could be affected not only by annealing but also by ultrasonic treatment. Photoluminescence measurement reveals that the ferromagnetism may relate to the defects that cause the 469 nm emission, and the products mainly show blue emission in the visible band after annealing. The low-cost and high-yield synthesis method makes the products promising materials for optoelectroic and spintronic devices.