High Sensitivity Piezogenerator Based on GaN Nanowires

We report on a prototype of piezogenerator based on vertically-aligned GaN nanowires grown by Plasma-Assisted Molecule Beam Epitaxy (PAMBE). Our device generates a peak-to-peak voltage from 20 mV to 60 mV depending on the applied force. The output power density reaches 0.76 mW/cm3 which is of the same order of magnitude as the state-of-art value. Furthermore, the pressure applied to deform the nanowires is of the order of kPa, much less than that used in previous reports (which were of the order of MPa) utilizing ZnO nanowires for the power generation. Thus, an enhanced mechanic-electrical conversion efficiency has been achieved. Our GaN nanowire based devices are promising both for pressure sensing applications and for mechanic energy harvesting