ZnO offers tremendous potential in future applications of electronic, optoelectronic, and
magnetoelectronic devices. Encouraging progress on the research of nanostructured ZnO
materials have been accomplished as reviewed in this article. There are still important issues
waiting to be further investigated. One key area is the growth of p-type ZnO nanowires and
fabrication of nanoscale p-n junctions for electrically driven nano LED or laser. Integration of
ZnO nanostructure building blocks for large scale device applications is another important
issue. Continuous effort is dedicated to achieve large arrays of programmable structures for
building reconfigurable architectures. Last but not the least, obtaining room temperature
ferromagnetism and demonstrating spin-polarized transport in ZnO nanostructures will greatly
advance future research on spin-based nanoscale devices.