We report on the fabrication of ZnO nanosheets on Graphene and other substrates at ambient conditions. The growth mechanism and the effect of the substrate are also discussed. Our synthesis method is based on sonochemical reaction of Zinc nitrate hexahydrate and hexamethylenetetramine in aqueous solutions. Extensive analysis by transmission electron microscopy, energy dispersive x-ray spectroscopy (EDS) revealed crystalline ZnO composition of the ZnO nanosheets. The proposed method is a rapid, inexpensive, low-temperature, catalystfree, CMOS compatible and environmentally benign alternative to existing growth techniques.