Polarity in ZnO nanowires: A critical issue for piezotronic and piezoelectric devices

The polar and piezoelectric nature of the wurtzite structure ZnO nanowires with a high aspect ratio at nanoscale dimensions is interest for piezotronic devices, but number issues related to polarity are still open deserve particular attention. In this context, chemical bath deposition offers unique opportunity select O- or Zn-polarity resultant further compatible fabrication processes flexible devices. control use in grown by new way greatly enhance performance However, as an additional tunable parameter should be considered care because it has strong influence on many properties. present review intended report most important consequences After introducing basic principles involving crystal ZnO, special emphasis placed effects nucleation growth mechanisms using deposition, defect incorporation doping, electrical contacts device