Abstract. ZnO nanostructures with different morphologies and optical properties were prepared by a simple microemulsion process, and PEG400 was used as a directing agent. The samples were characterized by TEM, XRD, FTIR, and TG-DTA analysis. The XRD spectra indicate that the ZnO crystal has a hexagonal wurtzite structure. Needle-like, columnar, and spherical ZnO samples were synthesized res…