Back Cover: GaN nanowires for piezoelectric generators (Phys. Status Solidi RRL 5/2014)
Noelle Gogneau, Pascal Chrétien, Elisabeth Galopin, Stephane Guilet, Laurent Travers, Jean-Christophe Harmand and Frédéric Houzé
Article first published online: 15 MAY 2014 | DOI: 10.1002/pssr.201470527
The semiconductor nanowires (NWs) presenting piezoelectric properties have recently emerged as excellent candidates to fabricate novel and efficient piezoelectric generators through the harvesting of mechanical deformations and vibrations energies. In particular, gallium nitride (GaN) NWs are characterized by both higher piezoelectric response and output voltages with respect to other piezoelectric material NWs. In their Letter on pp. 414–419, Noelle Gogneau et al. investigate the mechanical–electrical conversion of GaN NWs. An average output voltage of about –74 mV for a large NW ensemble and a maximum output voltage reaching –443 mV (±2%) per NW are demonstrated. This latter output voltage is the highest value reported so far for GaN NWs. Based on these measured output signals, an average and a maximum power density generated by one layer of GaN NWs of the order of 5.9 mW/cm2 and 130 mW/cm2, respectively, have been estimated. This result evidences the strong potentiality of GaN NWs to develop ultra-compact and integrable renewable energy source for sustainable, independent and maintenance-free operation of microdevices.