Nanoelectromechanical Sensors based on Suspended 2D Materials

The unique properties and atomic thickness of two-dimensional (2D) materials enable smaller and better nanoelectromechanical sensors with novel functionalities. During the last decade, many studies have successfully shown the feasibility of using suspended membranes of 2D materials in pressure sensors, microphones, accelerometers, and mass and gas sensors. In this review, we explain the different sensing concepts and give an overview of the relevant material properties, fabrication routes, and device operation principles. Finally, we discuss sensor readout and integration methods and provide comparisons against the state of the art to show both the challenges and promises of 2D material-based nanoelectromechanical sensing.Comment: Review pape

Nanomechanical Resonators: Toward Atomic Scale

The quest for realizing and manipulating ever smaller man-made movable structures and dynamical machines has spurred tremendous endeavors, led to important discoveries, and inspired researchers to venture to new grounds. Scientific feats and technological milestones of miniaturization of mechanical structures have been widely accomplished by advances in machining and sculpturing ever shrinking features out of bulk materials such as silicon. With the flourishing multidisciplinary field of low-dimensional nanomaterials, including one-dimensional (1D) nanowires/nanotubes, and two-dimensional (2D) atomic layers such as graphene/phosphorene, growing interests and sustained efforts have been devoted to creating mechanical devices toward the ultimate limit of miniaturization— genuinely down to the molecular or even atomic scale. These ultrasmall movable structures, particularly nanomechanical resonators that exploit the vibratory motion in these 1D and 2D nano-to-atomic-scale structures, offer exceptional device-level attributes, such as ultralow mass, ultrawide frequency tuning range, broad dynamic range, and ultralow power consumption, thus holding strong promises for both fundamental studies and engineering applications. In this Review, we offer a comprehensive overview and summary of this vibrant field, present the state-of-the-art devices and evaluate their specifications and performance, outline important achievements, and postulate future directions for studying these miniscule yet intriguing molecular-scale machines

Optimization of a CMOS-MEMS Resonator for Applications of Relative Humidity Measurement

The mathematical modeling and the finite element analysis (FEA) of a Complementary Metal Oxide Semiconductor-Microelectromechanical System (CMOS-MEMS) resonator has been presented. The resonator is designed based on 0.35 µm CMOS foundry fabrication technology. The sensing principle of the resonator is based on the change in resonance frequency of the CMOS-MEMS resonator due to adsorption/absorption or desorption of humidity on the active material layer of deposited on the moving plate that results in changes in the mass of the device. Simple analytical models of the CMOSMEMS resonator are generated to achieve estimates of the device performs. The effect of changes in lengths and widths of the beams on spring constant, resonance frequency, damping coefficient and quality factor (Q) are investigated. The spring constant is found to decrease with increase the lengths of the beam and increasing with increase the widths of the beam

Solid State Circuits Technologies

The evolution of solid-state circuit technology has a long history within a relatively short period of time. This technology has lead to the modern information society that connects us and tools, a large market, and many types of products and applications. The solid-state circuit technology continuously evolves via breakthroughs and improvements every year. This book is devoted to review and present novel approaches for some of the main issues involved in this exciting and vigorous technology. The book is composed of 22 chapters, written by authors coming from 30 different institutions located in 12 different countries throughout the Americas, Asia and Europe. Thus, reflecting the wide international contribution to the book. The broad range of subjects presented in the book offers a general overview of the main issues in modern solid-state circuit technology. Furthermore, the book offers an in depth analysis on specific subjects for specialists. We believe the book is of great scientific and educational value for many readers. I am profoundly indebted to the support provided by all of those involved in the work. First and foremost I would like to acknowledge and thank the authors who worked hard and generously agreed to share their results and knowledge. Second I would like to express my gratitude to the Intech team that invited me to edit the book and give me their full support and a fruitful experience while working together to combine this book

Novel Specialty Optical Fibers and Applications

Novel Specialty Optical Fibers and Applications focuses on the latest developments in specialty fiber technology and its applications. The aim of this reprint is to provide an overview of specialty optical fibers in terms of their technological developments and applications. Contributions include:1. Specialty fibers composed of special materials for new functionalities and applications in new spectral windows.2. Hollow-core fiber-based applications.3. Functionalized fibers.4. Structurally engineered fibers.5. Specialty fibers for distributed fiber sensors.6. Specialty fibers for communications

Advance in Energy Harvesters/Nanogenerators and Self-Powered Sensors

This reprint is a collection of the Special Issue "Advance in Energy Harvesters/Nanogenerators and Self-Powered Sensors" published in Nanomaterials, which includes one editorial, six novel research articles and four review articles, showcasing the very recent advances in energy-harvesting and self-powered sensing technologies. With its broad coverage of innovations in transducing/sensing mechanisms, material and structural designs, system integration and applications, as well as the timely reviews of the progress in energy harvesting and self-powered sensing technologies, this reprint could give readers an excellent overview of the challenges, opportunities, advancements and development trends of this rapidly evolving field

Micro-Resonators: The Quest for Superior Performance

Microelectromechanical resonators are no longer solely a subject of research in university and government labs; they have found a variety of applications at industrial scale, where their market is predicted to grow steadily. Nevertheless, many barriers to enhance their performance and further spread their application remain to be overcome. In this Special Issue, we will focus our attention to some of the persistent challenges of micro-/nano-resonators such as nonlinearity, temperature stability, acceleration sensitivity, limits of quality factor, and failure modes that require a more in-depth understanding of the physics of vibration at small scale. The goal is to seek innovative solutions that take advantage of unique material properties and original designs to push the performance of micro-resonators beyond what is conventionally achievable. Contributions from academia discussing less-known characteristics of micro-resonators and from industry depicting the challenges of large-scale implementation of resonators are encouraged with the hopes of further stimulating the growth of this field, which is rich with fascinating physics and challenging problems

Studies in Nonlinear and Stochastic Phenomena and Quality Factor Enhancement in a Nanomechanical Resonator

University of Minnesota M.S.M.E. thesis.July 2019. Major: Mechanical Engineering. Advisor: Subramanian Ramakrishnan. 1 computer file (PDF); xiii, 117 pages.Nonlinear damping has recently been experimentally observed in carbon nanotube and graphene-based nanoelectromechanical (NEMS) resonators and shown to be an effective means to achieve higher quality (Q) factors. Moreover, it has been shown that white noise excitation can be exploited to shrink the resonance width of the frequency response characteristics of the resonator as a pathway to higher Q factors. Motivated thus, this thesis is a study of certain fundamental characteristics of the nonlinear dynamics of a nanoelectromechanical resonator in both the deterministic and stochastic regimes with a focus on the influence of those characteristics on the Q factor. Using a Duffing oscillator based model, this thesis: (1) derives an analytical expression between oscillation amplitude and frequency of a NEMS resonator using the harmonic balance method to study the frequency response characteristics and validates the results using numerical simulation, (2) studies the deterministic dynamics of a NEMS resonator deriving an analytical relationship between the phase angle and maximum oscillation of the resonator response, (3) derives an analytical expression between the resonance frequency and resonance amplitude, (4) studies the hysteresis characteristics both in the stochastic and deterministic regimes elucidating the effects of nonlinear damping and external excitation on the hysteresis region, (5) finds that stochastic excitation with increasing intensity can shrink the hysteresis width, (6) shows that increasing the magnitude of the linear damping coefficient results in the decrease of Q-factors, (7) shows that in the combined presence of both parametric and external excitation, increasing the ratio of pump frequency to external forcing frequency results in lower resonant frequency and lower resonance width, (8) observes that in the parametrically driven nanomechanical resonator, higher parametric oscillation amplitude increases the resonance amplitude with a small impact on the resonance frequency, (9) solves the stochastic model using the Euler-Maruyama method and generates frequency response curves where it is found that higher noise intensity of Levy stable stochastic process can increase the Q factor, (10) finds that the Q factor is increased by decreasing the nonlinear damping and external harmonic driving amplitude. In summary, this thesis presents a set of novel results on the nonlinear, stochastic dynamics of a NEMS resonator and discusses the implications of the results for achieving enhanced Q factors. The results are of interest both from a theoretical viewpoint as well as in sensing applications using a nanoresonator