A nanomechanical mass sensor with yoctogram resolution (original) (raw)
Related papers
Fully integrated nanoresonator system with attogram/Hz mass resolution
2005
Nanoresonator systems have been fully integrated on preprocessed complementary metal oxide semiconductor (CMOS) chips. The systems have been used for high sensitivity mass sensing in air and vacuum. The resonator system, which consists of a cantilever and structures for electrostatic actuation and capacitive read-out, has been defined by low energy electron beam lithography (EBL) combined with direct write laser lithography (DWL) on top of a radiation sensitive CMOS layer. The fabrication of the nanoresonator system has been conducted as a postprocess step. CMOS integration radically decreases the parasitic capacitance, enabling detection and amplification of the resonance signal directly on the chip. Fabricated resonator systems have been designed to have resonance frequencies in the range of 1-1.6 MHz. A mass resolution of 3 ag/Hz has been determined in air by placing a single glycerine drop at the apex of a cantilever and subsequently measuring a frequency shift of 14.8 kHz. The frequency shift corresponds to an added mass of 50 fg, which is close to the estimated weight of 41 fg for the glycerine drop.
Micro/nanomechanical resonators for distributed mass sensing with capacitive detection
Microelectronic Engineering, 2006
Micro/nanomechanical resonators have been designed and fabricated with the aim to be used as distributed mass sensors for in situ measurement of the thickness of ultra-thin layers. First, we present a comparative study of three kinds of oscillating devices (cantilever, bridge and quad beam). The quad beam design has been selected for fabrication because it combines high sensitivity and good electrical response. The complete fabrication process of the device is based on electron beam lithography, lift-off and reactive ion etching. The frequency response has been characterized by means of electrical excitation and capacitive read-out.
Ultrasensitive force detection with a nanotube mechanical resonator
Nature Nanotechnology, 2013
Since the advent of atomic force microscopy [1], mechanical resonators have been used to study a wide variety of phenomena, such as the dynamics of individual electron spins [2], persistent currents in normal metal rings [3], and the Casimir force [4, 5]. Key to these experiments is the ability to measure weak forces. Here, we report on force sensing experiments with a sensitivity of 12 zN/ √ Hz at a temperature of 1.2 K using a resonator made of a carbon nanotube. An ultra-sensitive method based on cross-correlated electrical noise measurements, in combination with parametric downconversion, is used to detect the low-amplitude vibrations of the nanotube induced by weak forces. The force sensitivity is quantified by applying a known capacitive force. This detection method also allows us to measure the Brownian vibrations of the nanotube down to cryogenic temperatures. Force sensing with nanotube resonators offers new opportunities for detecting and manipulating individual nuclear spins as well as for magnetometry measurements.
Surface Area Enhancement of Nanomechanical Disk Resonators Using MWCNT for Mass Sensing Applications
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2018
This work presents fabrication of thermalpiezoresistive nanoelectromechanical (NEM) silicon disk resonators and their characterization as highly sensitive mass sensors. Forest of multiwall carbon nanotubes (MWCNT) has been grown on top surface of the fabricated devices increasing the resonator effective surface area, which in turn increases the adsorption capacity and therefore frequency shift of the sensor in molecular or particulate detection applications. To investigate the effect of the enhanced surface area on frequency shift, devices with and without MWCNTs were exposed to an aqueous solution of manganese sulfate for different deposition times and the resonance frequency shift was recorded accordingly. The measured frequency shift for the devices covered with MWCNTs was 14X higher than similar bare silicon devices. Furthermore, mass loading experiments were performed using gold nanoparticles as loading mass. A novel way to attach gold nanoparticles on the CNTs wall was developed here. Oxygen plasma treatment introduced dangling bonds on the MWCNTs walls to facilitate bonding between them and trimethoxysilane aldehyde molecules forming the surface assembly monolayer (SAM). After functionalization of the device with SAM and anti-influenza H1N1 viruses (AB), the device was exposed to a solution of Anti-Mouse IgG (whole molecule)-Gold antibody produced in goat products. The results showed more than 3 times response enhancement for the resonators with MWCNTs.
Investigation of Double Walled Carbon Nanotubes for Mass Sensing
Procedia Technology, 2014
This paper deals with studying the mass sensing characteristics of Double Walled carbon Nanotubes (DWCNT) using a continuum mechanics based approach. The interlayer separation in the form of Van der Waals interaction is modelled using characteristic spring element. The inner and outer walls of the nanotube are modelled as elastic beams with a spring element connecting the two layers. Two types of boundary conditions, i.e. cantilever and bridged are considered for the purpose of analysis. This analysis explores the resonant frequency shift of Double walled Carbon Nanotubes caused by the changes in the size in terms of length and masses. The results have shown that the dynamic characteristics are influenced by the change in length as well as masses attached to the centre and at the tip of DWCNT. The results also indicate that the mass sensing characteristics of DWCNT based nano balances can reach upto 0.1 Zeptogram. This investigation is further useful in the applications involving oscillators and sensors based on nano electromechanical devices vibrating at very high frequencies in the order of THz.
Nanotechnology, 2001
A simple linear electromechanical model for an electrostatically driven resonating cantilever is derived. The model has been developed in order to determine dynamic quantities such as the capacitive current flowing through the cantilever-driver system at the resonance frequency, and it allows us to calculate static magnitudes such as position and voltage of collapse or the voltage versus deflection characteristic. The model is used to demonstrate the theoretical sensitivity on the attogram scale of a mass sensor based on a nanometre-scale cantilever, and to analyse the effect of an extra feedback loop in the control circuit to increase the Q factor.
Computational Materials Science, 2013
A study of vibrational characteristics of double walled carbon nanotube modeled using spring elements and lumped masses has been performed. The inner and outer walls of carbon nanotube are modeled as two individual elastic beams interacting each other by van der Waals forces. To simulate the interlayer interactions and describe the van der Waals potentials between carbon atoms on different layers appropriate spring elements are utilized. This paper also investigates the mass recognition characteristics of double walled carbon nanotubes using analytical and finite element procedure. The effect of changes in outer length of the nanotube has been investigated by simulations keeping the inner wall length as constant. The shift in the resonant frequencies corresponding to the attached mass and different boundary conditions has been analyzed. Comparison with other theoretical studies reveals very good correlations in terms of the fundamental frequencies. This investigation is helpful in the applications involving high frequency oscillators and sensors based on nano-electromechanical devices requiring controlled length of inner and outer tubes of double walled carbon nanotube.
Ultrahigh Frequency Nanotube Resonators
Physical Review Letters, 2006
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 10 ÿ18 g resolution.