Browsing by Subject "Nanoelectromechanical systems"

Now showing 1 - 7 of 7

Open Access
Atmospheric pressure mass spectrometry of single viruses and nanoparticles by nanoelectromechanical systems
(American Chemical Society, 2022-01-04) Erdogan, R. Tufan; Alkhaled, Mohammed; Kaynak, Batuhan E.; Alhmoud, Hashim; Pisheh, Hadi Sedaghat; Kelleci, Mehmet; Karakurt, Ilbey; Yanik, C.; Şen, Zehra Betül; Sari, B.; Yagci, A. M.; Özkul, A.; Hanay, M. Selim
Mass spectrometry of intact nanoparticles and viruses can serve as a potent characterization tool for material science and biophysics. Inaccessible by widespread commercial techniques, the mass of single nanoparticles and viruses (>10MDa) can be readily measured by nanoelectromechanical systems (NEMS)-based mass spectrometry, where charged and isolated analyte particles are generated by electrospray ionization (ESI) in air and transported onto the NEMS resonator for capture and detection. However, the applicability of NEMS as a practical solution is hindered by their miniscule surface area, which results in poor limit-of-detection and low capture efficiency values. Another hindrance is the necessity to house the NEMS inside complex vacuum systems, which is required in part to focus analytes toward the miniscule detection surface of the NEMS. Here, we overcome both limitations by integrating an ion lens onto the NEMS chip. The ion lens is composed of a polymer layer, which charges up by receiving part of the ions incoming from the ESI tip and consequently starts to focus the analytes toward an open window aligned with the active area of the NEMS electrostatically. With this integrated system, we have detected the mass of gold and polystyrene nanoparticles under ambient conditions and with two orders-of-magnitude improvement in capture efficiency compared to the state-of-the-art. We then applied this technology to obtain the mass spectrum of SARS-CoV-2 and BoHV-1 virions. With the increase in analytical throughput, the simplicity of the overall setup, and the operation capability under ambient conditions, the technique demonstrates that NEMS mass spectrometry can be deployed for mass detection of engineered nanoparticles and biological samples efficiently.
Open Access
Atmospheric-pressure mass spectrometry by single-mode nanoelectromechanical systems
(American Chemical Society, 2023-09-08) Kaynak, Batuhan Emre; Alkhaled, Mohammed; Kartal, Enise; Yanık, Cenk; Hanay, Mehmet Selim
Weighing particles above the megadalton mass range has been a persistent challenge in commercial mass spectrometry. Recently, nanoelectromechanical systems-based mass spectrometry (NEMS-MS) has shown remarkable performance in this mass range, especially with the advance of performing mass spectrometry under entirely atmospheric conditions. This advance reduces the overall complexity and cost while increasing the limit of detection. However, this technique required the tracking of two mechanical modes and the accurate knowledge of mode shapes that may deviate from their ideal values, especially due to air damping. Here, we used a NEMS architecture with a central platform, which enables the calculation of mass by single-mode measurements. Experiments were conducted using polystyrene and gold nanoparticles to demonstrate the successful acquisition of mass spectra using a single mode with an improved areal capture efficiency. This advance represents a step forward in NEMS-MS, bringing it closer to becoming a practical application for the mass sensing of nanoparticles. © 2023 The Authors. Published by American Chemical Society.
Open Access
Comparison of geometric and drive-induced nonlinearities in doubly clamped, thermoelastic nanoelectromechanical systems
(TÜBİTAK, 2019-06) Hanay, Mehmet Selim
The performance of resonant sensors based on nanoelectromechanical systems depends critically on the maximum amplitude of oscillation reached in the linear regime. The maximum linear amplitude is determined by nonlinear mechanisms that can originate from the material, geometric and transduction mechanism related factors. Here we compare the two competing effects, the geometric and drive-induced nonlinearities, for a commonly used device family, the thermoelastically driven, doubly clamped beams. We find that the geometric nonlinearity dominates for most of the device designs used in the literature, however the drive-induced nonlinearity becomes the determining factor for thicker beams with small electrode lengths.
Open Access
An experimental approach to nanomechanical buckling and snap-through phenomenon
(2019-08) Hatipoğlu, Utku
Buckling has received little attention as a valuable resource for engineering applications since it is regarded as a type of failure in civil and mechanical engineering. Nevertheless, buckling has a great potential in nanoelectromechanical systems(NEMS) field as a bistable process that has rich and complex dynamics. Here, we explore post buckling dynamics of a nano-beam experimentally by employing various probing techniques. By employing an all-electronic architecture, we precisely control the buckling amount as well as buckling direction of the nano-beam which eventually gives us the ability to control a two-level mechanical system with high precision and speed. A full control over the potential energy landscape of the system is demonstrated with different techniques such as Scanning Electron Microscopy operated in three different modes and microwave coupling method. During proof of concept experiments, left and right buckling, large deflection buckling, nonvolatility – which is an indication of pure bistable states – and snap-through phenomenon is demonstrated. Further steps of the study focused on the snap-through phenomenon that is the interstate transitions of the buckling beam after bifurcation. During these experiments, more involved relations are investigated such as mechanical bias and effect of plastic deformation as well as the effect of actuation scheme on interstate jumps. Moreover, to obtain a better grasp of post-buckling dynamics, quantitative measurements are carried out which reveal the reaction speed of the system and time scale of interstate jumps. Lastly, oscillatory snap-through motion is observed in some special conditions that can be beneficial to understand noise dynamics of the system and it has a potential to contribute energy harvesting applications.
Embargo
Mode-dependent scaling of nonlinearity and linear dynamic range in a NEMS resonator
(AIP Publishing LLC, 2024-08-19) Ma, M.; Welles, N.; Svitelskiy, O.; Yanık, Cenk; Kaya, İsmet İnonu; Hanay, Mehmet Selim; Paul, M. R.; Ekinci, Kamil L.
Even a relatively weak drive force is enough to push a typical nanomechanical resonator into the nonlinear regime. Consequently, nonlinearities are widespread in nanomechanics and determine the critical characteristics of nanoelectromechanical systems' (NEMSs) resonators. A thorough understanding of the nonlinear dynamics of higher eigenmodes of NEMS resonators would be beneficial for progress, given their use in applications and fundamental studies. Here, we characterize the nonlinearity and the linear dynamic range (LDR) of each eigenmode of two nanomechanical beam resonators with different intrinsic tension values up to eigenmode n = 11. We find that the modal Duffing constant increases as n(4), while the critical amplitude for the onset of nonlinearity decreases as 1/n. The LDR, determined from the ratio of the critical amplitude to the thermal noise amplitude, increases weakly with n. Our findings are consistent with our theory treating the beam as a string, with the nonlinearity emerging from stretching at high amplitudes. These scaling laws, observed in experiments and validated theoretically, can be leveraged for pushing the limits of NEMS-based sensing even further.
Embargo
Nanomechanical and microwave resonance sensing for characterization of individual virions and nanoparticles in atmospheric conditions
(2023-09) Alkhaled, Mohammed
This dissertation focuses on Nanoelectromechanical-based Mass Spectrometry (NEMS-MS), an innovative technique for characterizing nanoparticles and biomolecules weighing above the working limit of commercial mass spectrometry tools. It suggests performing NEMS-MS under atmospheric conditions and enhancing its capabilities with a built-in focusing lens. Amid the COVID-19 pandemic, the study addresses urgent virus detection needs, proposing a label-free method using NEMS-MS for individual virus detection and characterization. Notably, the study achieves mass spectrometry measurement of the SARS-CoV-2 virus using a NEMS-MS system operating entirely under atmospheric pressure. As the first to pioneer NEMS-MS in air, the study examines challenges tied to this, particularly how NEMS response in dissipative environments, known as Mode Shape Attenuation. Mathematical models and experiments dissect factors contributing to this attenuation, resulting in improved mass spectra and contributing toward the utilization of NEMS-MS for real-world application. Taking innovation a step further, the study introduces a microwave-based sensor for inferring electrical properties of nanoparticles. This sensor works in the electro-magnetic domain, determining properties like dielectric constant and expanding the sensing possibilities. Overall, this dissertation propels NEMS-based sensing and characterization by combining mass spectrometry, microwave sensing, and atmospheric pressure operation. Addressing challenges and introducing innovative solutions, it advances NEMS-MS technology and offers a cost-effective tool for characterizing nanoparticles and biomolecules across various applications.
Open Access
Quantum turnstile regime of nanoelectromechanical systems
(American Physical Society, 2020) Dragomir, R.; Moldoveanu, V.; Stanciu, S.; Tanatar, Bilal
The effects of a turnstile operation on the current-induced vibron dynamics in nanoelectromechanical systems (NEMS) are analyzed in the framework of the generalized master equation. In our simulations each turnstile cycle allows the pumping of up to two interacting electrons across a biased mesoscopic subsystem which is electrostatically coupled to the vibrational mode of a nanoresonator. The time-dependent mean vibron number is very sensitive to the turnstile driving, rapidly increasing/decreasing along the charging/discharging sequences. This sequence of heating and cooling cycles experienced by the nanoresonator is due to specific vibron-assisted sequential tunneling processes along a turnstile period. At the end of each charging/discharging cycle the nanoresonator is described by a linear combination of vibron-dressed states sν associated to an electronic configuration ν. If the turnstile operation leads to complete electronic depletion the nanoresonator returns to its equilibrium position, i.e., its displacement vanishes. It turns out that a suitable bias applied on the NEMS leads to a slow but complete cooling at the end of the turnstile cycle. Our calculations show that the quantum turnstile regime switches the dynamics of the NEMS between vibron-dressed subspaces with different electronic occupation numbers. We predict that the turnstile control of the electron-vibron interaction induces measurable changes on the input and output transient currents.