Realization and direct observation of five normal and parametric modes in silicon nanowire resonators by in situ transmission electron microscopy

Publication date
DOI http://dx.doi.org/10.1039/c8na00373d
Reference F.-C. Hsia, D.-M. Tang, W. Jevasuwan, N. Fukata, X. Zhou, M. Mitome, Y. Bando, T.E.M. Nordling and D. Golberg, Realization and direct observation of five normal and parametric modes in silicon nanowire resonators by in situ transmission electron microscopy, Nanoscale Adv. 1, 5: 1784-1790 (2019)

Mechanical resonators have wide applications in sensing bio-chemical substances, and provide an accurate method to measure the intrinsic elastic properties of oscillating materials. A high resonance order with high response frequency and a small resonator mass are critical for enhancing the sensitivity and precision. Here, we report on the realization and direct observation of high-order and high-frequency silicon nanowire (Si NW) resonators. By using an oscillating electric-field for inducing a mechanical resonance of single-crystalline Si NWs inside a transmission electron microscope (TEM), we observed resonance up to the 5th order, for both normal and parametric modes at ∼100 MHz frequencies. The precision of the resonant frequency was enhanced, as the deviation reduced from 3.14% at the 1st order to 0.25% at the 5th order, correlating with the increase of energy dissipation. The elastic modulus of Si NWs was measured to be ∼169 GPa in the [110] direction, and size scaling effects were found to be absent down to the ∼20 nm level.