Nanostructured ZnO: Building blocks for nanoscale devices

ZnO is attracting intensive attention for its versatile applications in transparent electronics, UV emitter, piezoelectric devices, chemical sensor and spin electronics. As one of the direct wide band gap semiconductors, it has advantages over GaN due to its larger exciton binding energy, better lattice match on heteroepitaxial growth and availability of single crystal substrate. Large effort has been invested in the growth of nanostructured ZnO to explore its potentials for nanoscale device applications. ZnO nanobelts, nanowires, nanorings, and nanohelixes demonstrate the diversity of ZnO nanostructures family. This review presents recent research on ZnO nanostructures. Issues of synthesis methods, optical, electrical, gas sensing and magnetic properties are summarized. These progresses constitute the basis for developing future applications in nanoscale electronics, optoelectronics, chemical sensor and spintronics.