High-quality nanomechanical resonator based on a defect-free gold nanowire

Nanomechanical resonators were fabricated using defect-free single-crystalline Au nanowires (NWs), and their mechanical properties were investigated by using the magneto-motive detection method. The fabricated Au NW resonators exhibited a resonance frequency of 33-119 MHz and a quality factor of 1800 ∼ 11000, depending on the resonator's dimensions. Compared to its amorphous film counterpart, the Au NW resonator showed noticeable increases in both the resonance frequency and the quality factor. Also observed was a significant increase in the dynamic range for the NW resonator. These improvements could be attributed to low and uniform energy dissipation by the defect-free single-crystalline Au NW resonator. In addition, the length dependence of the nonlinear characteristics was observed. Mechanical softening was observed in the case of short (l = 2 μm and 3 μm) resonators while mechanical hardening was observed in the case of long (l = 4 μm) resonators.