Dual-mode mechanical resonance of individual ZnO nanobelts

The mechanical resonance of a single ZnO nanobelt, induced by an alternative electric field, was studied by in situ transmission electron microscopy. Due to the rectangular cross section of the nanobelt, two fundamental resonance modes have been observed corresponding to two orthogonal transverse vibration directions, showing the versatile applications of nanobelts as nanocantilevers and nanoresonators. The bending modulus of the ZnO nanobelts was measured to be ∼52 GPa and the damping time constant of the resonance in a vacuum of 5×10−8 Torr was ∼1.2 ms and quality factor Q=500.