Fast measurement of carbon nanotube resonator amplitude with a heterojunction bipolar transistor

Abstract

Carbon nanotube (CNT) electromechanical resonators have demonstrated unprecedented sensitivities for detecting small masses and forces. The detection speed in a cryogenic setup is usually limited by the CNT contact resistance and parasitic capacitance. We report the use of a heterojunction bipolar transistor (HBT) amplifying circuit near the device to measure the mechanical amplitude at microsecond timescales. A Coulomb rectification scheme, in which the probe signal is at much lower frequency than the mechanical drive signal, allows investigation of the strongly non-linear regime. The behaviour of transients in both the linear and non-linear regimes is observed and modeled by including Duffing and non-linear damping terms in a harmonic oscillator equation. We show that the non-linear regime can result in faster mechanical response times, on the order of 10 microseconds for the device and circuit presented, potentially enabling the magnetic moments of single molecules to be measured within their spin relaxation and dephasing timescales.

Pages 1-5 are the main paper, pages 6-8 are supplementary material

References in corpus (8)

• A Mechanical Mass Sensor with Yoctogram Resolution
• Will spin-relaxation times in molecular magnets permit quantum information processing?
• Strong coupling between single-electron tunneling and nano-mechanical motion
• Carbon nanotubes as ultra-high quality factor mechanical resonators
• Nanotube mechanical resonators with quality factors of up to 5 million
• Digital and FM demodulation of a doubly-clamped single wall carbon nanotube oscillator: towards a nanotube cell phone
• Observation of decoherence in a carbon nanotube mechanical resonator
• Cryogenic preamplification of a single-electron-transistor using a silicon-germanium heterojunction-bipolar-transistor