High quality factor mechanical resonance in a silicon nanowire

Resonance properties of nanomechanical resonators based on doubly clamped silicon nanowires, fabricated from silicon-on-insulator and coated with a thin layer of aluminum, were experimentally investigated. Resonance frequencies of the fundamental mode were measured at a temperature of $20$ mK for nanowires of various sizes using the magnetomotive scheme. The measured values of the resonance frequency agree with the estimates obtained from the Euler–Bernoulli theory. The measured internal quality factor of the $5 \mu $m-long resonator, $3.62 \times 10^4$, exceeds the corresponding values of similar resonators investigated at higher temperatures. The structures presented can be used as mass sensors with an expected sensitivity $\sim 6 \times 10^{-20}\,\text{g} \text{Hz}^{-1/2}$.