A Mechanical Mass Sensor with Yoctogram Resolution

TL;DR

This paper demonstrates a carbon nanotube resonator capable of detecting masses as small as a single proton, enabling highly sensitive measurements for applications in mass spectrometry and surface science.

Contribution

It introduces a NEMS-based mass sensor with yoctogram resolution, surpassing previous sensitivities and enabling detection of individual molecules and atoms.

Findings

Mass resolution of 1.7 yg achieved

Detection of naphthalene molecule adsorption

Measurement of Xe atom binding energy (131 meV)

Abstract

Nanoelectromechanical systems (NEMS) have generated considerable interest as inertial mass sensors. NEMS resonators have been used to weigh cells, biomolecules, and gas molecules, creating many new possibilities for biological and chemical analysis [1-4]. Recently, NEMS-based mass sensors have been employed as a new tool in surface science in order to study e.g. the phase transitions or the diffusion of adsorbed atoms on nanoscale objects [5-7]. A key point in all these experiments is the ability to resolve small masses. Here we report on mass sensing experiments with a resolution of 1.7 yg (1 yg = 10^-24 g), which corresponds to the mass of one proton, or one hydrogen atom. The resonator is made of a ~150 nm long carbon nanotube resonator vibrating at nearly 2 GHz. The unprecedented level of sensitivity allows us to detect adsorption events of naphthalene molecules (C10H8) and to measure the binding energy of a Xe atom on the nanotube surface (131 meV). These ultrasensitive nanotube resonators offer new opportunities for mass spectrometry, magnetometry, and adsorption experiments.