Nano‐Newton Transverse Force Sensor Using a Vertical GaN Nanowire based on the Piezotronic Effect

In this paper, we explore the piezotronic effect in a GaN nanowire under a transverse force. The force was applied by bending the end of a single NW using an atomic force microscope (AFM) tip. Our results show that GaN NWs can be used to transduce a shear/bending force into a dramatic current change through the NW due to the piezotronic effect. Owing to the local piezopotential generated by the applied force, the barrier height of the Schottky contact between the GaN NW and the platinum AFM tip can be modulated. Using this transduction mechanism, the transverse force can be correlated to the natural logarithm of the current. Our results indicate that the force sensitivity is about 1.24 ± 0.13 ln(A)/nN, and a force resolution better than 16 nN is demonstrated. The nN sensitivity of GaN NWs shows the potential for piezoelectric semiconductor NWs to act as the main building blocks for micro-/nanometersized force sensor arrays and high spatial resolution artifi cial skin.