Q‐factor study of nanomechanical system “metal tip – carbon nanowhisker” at low and ambient pressure

Abstract

Nanomechanical oscillators based on amorphous carbon whiskers, localized on the top of tungsten tip were fabricated and investigated. The whiskers were grown in the scanning electron microscope chamber using focused electron beam technique. Oscillation trajectories and amplitude-frequency characteristic of the oscillator were visualized at low and ambient pressure using a scanning electron microscope and a confocal laser-scanning microscope, respectively. We experimentally show that at ambient pressure, the resonant frequency decreases significantly but the Q-factor of the oscillator unexpectedly increases with respect to experimental data acquired at low pressure. The explanation was provided taking into account the role of thin water layer absorbed on the whisker from atmosphere. The model of the coupled oscillators is considered.

Parametric Optothermal Modulation of Carbon Nanooscillator Decorated with Mie Resonant Silicon Particle

“…The geometry of the structures can be fully controlled in three‐dimensions (3D) by positioning the electron beam forming wired structures. [ 11,26,27 ] The material of EBID‐synthesized nanostructures is identified as a graphitic amorphous carbon with high sp 2 ‐fraction, which properties are close to glassy carbon, [ 28 ] and its density is estimated as 2.2 gcm −3 . [ 27 ] Figure 1b shows SEM image of the synthesized cylindrical NW with length L = 5.38 $$\umu{\rm m}$$, average diameter d = 164 nm and estimated mass is 250 fg.…”

Resonant Mass Detector Based on Carbon Nanowhiskers with Traps for Nanoobjects Weighing

“…Generally, Q‐factor of conventional mechanical oscillator falls when the oscillator is placed in a more viscous medium. Nevertheless, we experimentally demonstrated that in case of NMO (based on CNW with diameter of ≈100 nm and resonance frequency ≈10 MHz located on the top of the W tip) the Q‐factor remains the same value in vacuum and at ambient conditions . This fact makes the technique applicable for work with biological objects.…”

“…To control CNW size and shape, in contrast to the specialized rotary device was installed in the vacuum chamber of SEM, which allows to control the shape of growing nanowhiskers in front and side view. The created structures were rotated to 90°.…”

“…The development of nanofabrication techniques led to the creation of a variety of nanoelectromechanical sensors, including nanomechanical oscillators (NMO) . Due to submicron sizes these resonators have low weight and high resonance frequency, which provides high sensitivity and allows to weigh micro‐ and nanoobjects.…”