Ultrahigh Frequency Nanotube Resonators

We report carbon-nanotube-based electromechanical resonators with the fundamental mode frequency over 1.3 GHz, operated in air at room temperature. A new combination of drive and detection methods allows for unprecedented measurement of both oscillation amplitude and phase and elucidates the relative mobility of static charges near the nanotube. The resonator serves as an exceptionally sensitive mass detector capable of $\sim {10}^{-18}\mathrm{g}$ resolution.