ZnO nanoparticles were prepared by citric acid assisted microwave solution combustion method and its microstructure and optoelectronic properties had been investigated. The XRD, TEM, SEM and FT-IR analyses confirm that the ZnO crystallites with the hexagonal wurzite structure were directly formed. The crystalline grain size of ZnO was 9 nm and its specific surface area reached 19 m(2)/g. The room temperature photoluminescence proved that it had a blue emission, which increased remarkably with treated temperatures.

Keywords: ZnO; Citric acid; Nanocrystalline; Combustion; Microwave synthesis