Ultralow superharmonic resonance for functional nanowires.
Functional nanowires, made from materials such as zinc oxide, offer the promise of energy scavenging and precise sensing due to their vibrational properties, but their high intrinsic resonance frequencies (in the kilohertz to megahertz range) have limited the applications in nanotechnology. In this paper, we describe a method for introducing a new type of resonance at ultralow frequencies in ZnO nanowires. By using in situ ion implantation, nanodevice assembly, electronic signal generation, mechanical measurement, and electron beam characterization, we have achieved resonance at frequencies two orders of magnitude lower than the natural resonance frequency. Through both experimental investigation and theoretical simulation, we show that electric charge imbalance arising from focused ion beam exposure is responsible for the creation of this unprecedented superharmonic resonance behavior in ZnO nanowires.