Energy Harvesting Using Piezoelectric Nanowires-A Correspondence on "Energy Harvesting Using Nanowires?" by Alexe et al.

An experiment was carried out to demonstrate and analyze the questions raised and data presented by Alexe and colleagues, regarding energy harvesting using nanowires (NW). A piezoelectric potential field is created in the NW when a ZnO NW is elastically deformed. The piezoelectric potential is created by the polarization of ions in the crystal rather than the free-mobile charges. Since the charges associated with the ions are rigid and affixed to the atoms, they cannot freely move. Alexe and colleagues' experiments were based on an AFM measurement system that is dominated by large system artifacts and a noise comparable or even higher than the piezoelectric signals from a tiny NW. The only evidence presented by Alexe and researchers was that they received some discharge peaks from Si nanowires that were identical to that from ZnO. The NG is based on a piezoelectric effect, and it is a result of coupled piezoelectric and semiconducting dual properties of ZnO with the presence of a Schottky barrier between the metal tip and the NW.