Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
4.7
3.4
Journals
Micromachines
Special Issues
MEMS/NEMS Sensors: Fabrication and Application, Volume II
share announcement

MEMS/NEMS Sensors: Fabrication and Application, Volume II

A special issue of Micromachines (ISSN 2072-666X). This special issue belongs to the section "A：Physics".

Deadline for manuscript submissions: closed (1 April 2020) | Viewed by 71155

Special Issue Editors

Prof. Dr. Goutam Koley

E-Mail Website
Guest Editor
Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, USA
Interests: III-Nitride MEMS; chemical sensors; biosensors; 2D materials; nanoelectronics
Special Issues, Collections and Topics in MDPI journals
Dr. Ifat Jahangir

E-Mail Website
Guest Editor
Intel Corporation, OR 97124, USA
Interests: III-Nitride MEMS; 2D materials; nanowires; nanoelectronics; chemical sensors
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

As a result of the ever-expanding applications of micro- and nano-electromechanical systems (NEMS/MEMS) as sensors and actuators, interest in their development has rapidly expanded over the past decade. Encompassing various excitation and readout schemes, the MEMS/NEMS devices transduce physical parameter changes, such as temperature, mass, or stress, caused by alterations in desired measurands, to electrical signals that can be further processed. Some common examples of NEMS/MEMS sensors include pressure sensors, accelerometers, magnetic field sensors, microphones, radiation sensors, and particulate matter sensors.

Despite a long history of development, the fabrication of novel MEMS/NEMS devices still poses unique challenges due to their requirement for a suspended geometry. Many new fabrication techniques have been proposed to overcome these challenges. However, further development of these techniques is still necessary, as newer materials such as compound semiconductors and two-dimensional materials are finding their way in various MEMS/NEMS applications, with more complex structures and potentially smaller dimensions.

For this Special Issue, you are invited to submit contributions describing developments in the broad area of MEMS/NEMS-based sensors ranging from nanoscale to macroscale in dimensions and operating over a large range of frequencies, from GHz to a few Hz. The scope of this Special Issue covers different types of individual MEMS/NEMS sensors—made with traditional and emerging materials by employing various transduction schemes, sensor networks, and multimodal data fusion—theory and applications, physical models, and fabrication techniques.

Prof. Dr. Goutam Koley
Dr. Ifat Jahangir
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • MEMS/NEMS Sensors
  • Sensor fabrication
  • Physical sensors
  • Chemical sensors
  • Biological sensors
  • Radiation sensors

Published Papers (22 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

Jump to: Review, Other

12 pages, 3849 KiB  
Article
Investigation of AlGaN/GaN HFET and VO2 Thin Film Based Deflection Transducers Embedded in GaN Microcantilevers
by Ferhat Bayram, Durga Gajula, Digangana Khan and Goutam Koley
Micromachines 2020, 11(9), 875; https://doi.org/10.3390/mi11090875 - 20 Sep 2020
Cited by 3 | Viewed by 2244
Abstract
The static and dynamic deflection transducing performances of piezotransistive AlGaN/GaN heterojunction field effect transistors (HFET) and piezoresistive VO2 thin films, fabricated on GaN microcantilevers of similar dimensions, were investigated. Deflection sensitivities were tuned with the gate bias and operating temperature for embedded [...] Read more.
The static and dynamic deflection transducing performances of piezotransistive AlGaN/GaN heterojunction field effect transistors (HFET) and piezoresistive VO2 thin films, fabricated on GaN microcantilevers of similar dimensions, were investigated. Deflection sensitivities were tuned with the gate bias and operating temperature for embedded AlGaN/GaN HFET and VO2 thin film transducers, respectively. The GaN microcantilevers were excited with a piezoactuator in their linear and nonlinear oscillation regions of the fundamental oscillatory mode. In the linear regime, the maximum deflection sensitivity of piezotransistive AlGaN/GaN HFET reached up to a 0.5% change in applied drain voltage, while the responsivity of the piezoresistive VO2 thin film based deflection transducer reached a maximum value of 0.36% change in applied drain current. The effects of the gate bias and the operation temperature on nonlinear behaviors of the microcantilevers were also experimentally examined. Static deflection sensitivity measurements demonstrated a large change of 16% in drain-source resistance of the AlGaN/GaN HFET, and a similarly high 11% change in drain-source resistance in the VO2 thin film, corresponding to a 10 μm downward step bending of the cantilever free end. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

13 pages, 2479 KiB  
Article
Flexible Electrocorticography Electrode Array for Epileptiform Electrical Activity Recording under Glutamate and GABA Modulation on the Primary Somatosensory Cortex of Rats
by Xinrong Li, Yilin Song, Guihua Xiao, Jingyu Xie, Yuchuan Dai, Yu Xing, Enhui He, Yun Wang, Shengwei Xu, Lulu Zhang, Duli Yu, Tiger H. Tao and Xinxia Cai
Micromachines 2020, 11(8), 732; https://doi.org/10.3390/mi11080732 - 29 Jul 2020
Cited by 14 | Viewed by 3290
Abstract
Epilepsy is a common neurological disorder. There is still a lack of methods to accurately detect cortical activity and locate lesions. In this work, a flexible electrocorticography (ECoG) electrode array based on polydimethylsiloxane (PDMS)-parylene was fabricated to detect epileptiform activity under glutamate (Glu) [...] Read more.
Epilepsy is a common neurological disorder. There is still a lack of methods to accurately detect cortical activity and locate lesions. In this work, a flexible electrocorticography (ECoG) electrode array based on polydimethylsiloxane (PDMS)-parylene was fabricated to detect epileptiform activity under glutamate (Glu) and gamma-aminobutyric acid (GABA) modulation on primary somatosensory cortex of rats. The electrode with a thickness of 20 μm has good flexibility to establish reliable contact with the cortex. Fourteen recording sites with a diameter of 60 μm are modified by electroplating platinum black nanoparticles, which effectively improve the performance with lower impedance, obtaining a sensitive sensing interface. The electrode enables real-time capturing changes in neural activity under drug modulation. Under Glu modulation, neuronal populations showed abnormal excitability, manifested as hypsarrhythmia rhythm and continuous or periodic spike wave epileptiform activity, with power increasing significantly. Under GABA modulation, the excitement was inhibited, with amplitude and power reduced to normal. The flexible ECoG electrode array could monitor cortical activity, providing us with an effective tool for further studying epilepsy and locating lesions. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

12 pages, 3027 KiB  
Article
Etching of Uncompensated Convex Corners with Sides along <n10> and <100> in 25 wt% TMAH at 80 °C
by Milče M. Smiljanić, Žarko Lazić, Vesna Jović, Branislav Radjenović and Marija Radmilović-Radjenović
Micromachines 2020, 11(3), 253; https://doi.org/10.3390/mi11030253 - 27 Feb 2020
Cited by 4 | Viewed by 2561
Abstract
This paper presents etching of convex corners with sides along <n10> and <100> crystallographic directions in a 25 wt% tetramethylammonium hydroxide (TMAH) water solution at 80 °C. We analyzed parallelograms as the mask patterns for anisotropic wet etching of Si (100). The sides [...] Read more.
This paper presents etching of convex corners with sides along <n10> and <100> crystallographic directions in a 25 wt% tetramethylammonium hydroxide (TMAH) water solution at 80 °C. We analyzed parallelograms as the mask patterns for anisotropic wet etching of Si (100). The sides of the parallelograms were designed along <n10> and <100> crystallographic directions (1 < n < 8). The acute corners of islands in the masking layer formed by <n10> and <100> crystallographic directions were smaller than 45°. All the crystallographic planes that appeared during etching in the experiment were determined. We found that the obtained types of 3D silicon shape sustain when n > 2. The convex corners were not distorted during etching. Therefore, no convex corner compensation is necessary. We fabricated three matrices of parallelograms with sides along crystallographic directions <310> and <100> as examples for possible applications. Additionally, the etching of matrices was simulated by the level set method. We obtained a good agreement between experiments and simulations. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Graphical abstract

14 pages, 4471 KiB  
Article
The Characteristics and Locking Process of Nonlinear MEMS Gyroscopes
by Yan Su, Pengfei Xu, Guowei Han, Chaowei Si, Jin Ning and Fuhua Yang
Micromachines 2020, 11(2), 233; https://doi.org/10.3390/mi11020233 - 24 Feb 2020
Cited by 19 | Viewed by 2695
Abstract
With the miniaturization of micro-electro-mechanical system (MEMS) gyroscopes, it is necessary to study their nonlinearity. The phase-frequency characteristics, which affect the start-up time, are crucial for guaranteeing the gyroscopes’ applicability. Nevertheless, although the amplitude-frequency (A-f) effect, one of the most obvious problems in [...] Read more.
With the miniaturization of micro-electro-mechanical system (MEMS) gyroscopes, it is necessary to study their nonlinearity. The phase-frequency characteristics, which affect the start-up time, are crucial for guaranteeing the gyroscopes’ applicability. Nevertheless, although the amplitude-frequency (A-f) effect, one of the most obvious problems in nonlinearity, has been well studied, the phase response of nonlinear gyroscopes is rarely mentioned. In this work, an elaborate study on the characteristics and locking process of nonlinear MEMS gyroscopes is reported. We solved the dynamic equation using the harmonic balance method and simulated the phase-locked loop (PLL) actuation process with an iterative calculation method. It was shown that there existed an apparent overhanging and multi-valued phenomenon in both the amplitude–frequency and phase–frequency curves of nonlinear gyroscopes. Meanwhile, it was ascertained by our simulations that the locking time of PLL was retarded by the nonlinearity under certain conditions. Moreover, experiments demonstrating the effect of nonlinearity were aggravated by the high quality factor of the drive mode due to the instability of the vibration amplitude. A nonlinear PLL (NPLL) containing an integrator was designed to accelerate the locking process. The results show that the start-up time was reduced by an order of magnitude when the appropriate integral coefficient was used. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

13 pages, 10710 KiB  
Article
Inductive Magnetic Nanoparticle Sensor Based on Microfluidic Chip Oil Detection Technology
by Chenzhao Bai, Hongpeng Zhang, Lin Zeng, Xupeng Zhao and Laihao Ma
Micromachines 2020, 11(2), 183; https://doi.org/10.3390/mi11020183 - 10 Feb 2020
Cited by 31 | Viewed by 3470
Abstract
The wear debris in hydraulic oil or lubricating oil has a wealth of equipment operating information, which is an important basis for large mechanical equipment detection and fault diagnosis. Based on traditional inductive oil detection technology, magnetic nanoparticles are exploited in this paper. [...] Read more.
The wear debris in hydraulic oil or lubricating oil has a wealth of equipment operating information, which is an important basis for large mechanical equipment detection and fault diagnosis. Based on traditional inductive oil detection technology, magnetic nanoparticles are exploited in this paper. A new inductive oil detection sensor is designed based on the characteristics of magnetic nanoparticles. The sensor improves detection sensitivity based on distinguishing between ferromagnetic and non-ferromagnetic wear debris. Magnetic nanoparticles increase the internal magnetic field strength of the solenoid coil and the stability of the internal magnetic field of the solenoid coil. During the experiment, the optimal position of the sensor microchannel was first determined, then the effect of the magnetic nanoparticles on the sensor’s detection was confirmed, and finally the concentration ratio of the mixture was determined. The experimental results show that the inductive oil detection sensor made of magnetic nanoparticle material had a higher detection effect, and the signal-to-noise ratio (SNR) of 20–70 μm ferromagnetic particles was increased by 20%–25%. The detection signal-to-noise ratio (SNR) of 80–130 μm non-ferromagnetic particles was increased by 16%–20%. The application of magnetic nanoparticles is a new method in the field of oil detection, which is of great significance for fault diagnosis and the life prediction of hydraulic systems. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

13 pages, 6114 KiB  
Article
Active Thermoelectric Vacuum Sensor Based on Frequency Modulation
by Shu-Jung Chen and Yung-Chuan Wu
Micromachines 2020, 11(1), 15; https://doi.org/10.3390/mi11010015 - 21 Dec 2019
Cited by 8 | Viewed by 2912
Abstract
This paper introduces a thermoelectric-type sensor with a built-in heater as an alternative approach to the measurement of vacuum pressure based on frequency modulation. The proposed sensor is fabricated using the TSMC (Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan) 0.35 μm complementary metal-oxide-semiconductor-microelectro-mechanical systems [...] Read more.
This paper introduces a thermoelectric-type sensor with a built-in heater as an alternative approach to the measurement of vacuum pressure based on frequency modulation. The proposed sensor is fabricated using the TSMC (Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan) 0.35 μm complementary metal-oxide-semiconductor-microelectro-mechanical systems (CMOS–MEMS) process with thermocouples positioned central-symmetrically. The proposed frequency modulation technique involves locking the sensor output signal at a given frequency using a phase-lock-loop (PLL) amplifier to increase the signal-to-noise ratio (SNR) and thereby enhance the sensitivity of vacuum measurements. An improved first harmonic signal detection based on asymmetrical applied heating gives a precise measurement. Following calibration, the output voltage is in good agreement with the calibration values, resulting in an error of 0.25% under pressures between 0.1–10 Torr. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

17 pages, 8568 KiB  
Article
A Tuning Fork Gyroscope with a Polygon-Shaped Vibration Beam
by Qiang Xu, Zhanqiang Hou, Yunbin Kuang, Tongqiao Miao, Fenlan Ou, Ming Zhuo, Dingbang Xiao and Xuezhong Wu
Micromachines 2019, 10(12), 813; https://doi.org/10.3390/mi10120813 - 25 Nov 2019
Cited by 12 | Viewed by 3939
Abstract
In this paper, a tuning fork gyroscope with a polygon-shaped vibration beam is proposed. The vibration structure of the gyroscope consists of a polygon-shaped vibration beam, two supporting beams, and four vibration masts. The spindle azimuth of the vibration beam is critical for [...] Read more.
In this paper, a tuning fork gyroscope with a polygon-shaped vibration beam is proposed. The vibration structure of the gyroscope consists of a polygon-shaped vibration beam, two supporting beams, and four vibration masts. The spindle azimuth of the vibration beam is critical for performance improvement. As the spindle azimuth increases, the proposed vibration structure generates more driving amplitude and reduces the initial capacitance gap, so as to improve the signal-to-noise ratio (SNR) of the gyroscope. However, after taking the driving amplitude and the driving voltage into consideration comprehensively, the optimized spindle azimuth of the vibration beam is designed in an appropriate range. Then, both wet etching and dry etching processes are applied to its manufacture. After that, the fabricated gyroscope is packaged in a vacuum ceramic tube after bonding. Combining automatic gain control and weak capacitance detection technology, the closed-loop control circuit of the drive mode is implemented, and high precision output circuit is achieved for the gyroscope. Finally, the proposed Micro Electro Mechanical Systems (MEMS) gyroscope system demonstrates a bias instability of 0.589°/h, an angular random walk (ARW) of 0.038°/√h, and a bandwidth of greater than 100 Hz in a full scale range of ± 200°/s at room temperature. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Graphical abstract

13 pages, 8192 KiB  
Article
The Analysis of the Influence of Threshold on the Dynamic Contact Process of a Fabricated Vertically Driven MEMS Inertial Switch
by Wenguo Chen, Rui Wang, Huiying Wang, Dejian Kong and Shulei Sun
Micromachines 2019, 10(11), 791; https://doi.org/10.3390/mi10110791 - 18 Nov 2019
Cited by 2 | Viewed by 2297
Abstract
In this work, to evaluate the influence of the threshold on the dynamic contact process, five models (number 1, 2, 3, 4, 5) with different thresholds were proposed and fabricated with surface micromachining technology. The contact time and response time were used to [...] Read more.
In this work, to evaluate the influence of the threshold on the dynamic contact process, five models (number 1, 2, 3, 4, 5) with different thresholds were proposed and fabricated with surface micromachining technology. The contact time and response time were used to characterize the dynamic contact performance. The dynamic contact processes of the inertial switches with gradually increasing thresholds were researched using analytical, simulation, and experimental methods. The basic working principle analysis of the inertial switch shows that the contact time of the inertial switch with a low-g value can be extended by using a simply supported beam as the fixed electrode, but the high-G inertial needs more elasticity for fixed electrode. The simulation results indicate that the response time and contact time decrease with the increment in the designed threshold. Prototypes were tested using a dropping hammer system, and the test result indicates that the contact time of the inertial switch with a fixed electrode of the simply supported beam is about 15 and 5 μs when the threshold is about 280 and 580 g, respectively. Meanwhile, the contact time can be extended to 100 μs for the inertial switch using a spring as the fixed electrode when the threshold is about 280 and 580 g. These test results not only prove that the spring fixed electrode can effectively extend the contact time, but also prove that the style of the fixed electrode is the deciding factor affecting the contact time of the high-G inertial switch. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

17 pages, 4098 KiB  
Article
Design and Fabrication Challenges of a Highly Sensitive Thermoelectric-Based Hydrogen Gas Sensor
by Anmona Shabnam Pranti, Daniel Loof, Sebastian Kunz, Volkmar Zielasek, Marcus Bäumer and Walter Lang
Micromachines 2019, 10(10), 650; https://doi.org/10.3390/mi10100650 - 27 Sep 2019
Cited by 12 | Viewed by 2729
Abstract
This paper presents a highly sensitive thermoelectric sensor for catalytic combustible gas detection. The sensor contains two low-stress (+176 MPa) membranes of a combination of stoichiometric and silicon-rich silicon nitride that makes them chemically and thermally stable. The complete fabrication process with details, [...] Read more.
This paper presents a highly sensitive thermoelectric sensor for catalytic combustible gas detection. The sensor contains two low-stress (+176 MPa) membranes of a combination of stoichiometric and silicon-rich silicon nitride that makes them chemically and thermally stable. The complete fabrication process with details, especially the challenges and their solutions, is discussed elaborately. In addition, a comprehensive evaluation of design criteria and a comparative analysis of different sensor designs are performed with respect to the homogeneity of the temperature field on the membrane, power consumption, and thermal sensitivity. Evaluating the respective tradeoffs, the best design is selected. The selected sensor has a linear thermal characteristic with a sensitivity of 6.54 mV/K. Additionally, the temperature profile on the membrane is quite homogeneous (20% root mean standard deviation), which is important for the stability of the catalytic layer. Most importantly, the sensor with a ligand (p-Phenylenediamine (PDA))-linked platinum nanoparticles catalyst shows exceptionally high response to hydrogen gas, i.e., 752 mV at 2% concentration. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

13 pages, 3655 KiB  
Article
Design and Analysis of Particulate Matter Air-Microfluidic Grading Chip Based on MEMS
by Tingting Chen, Jianhai Sun, Tianjun Ma, Tong Li, Chang Liu, Xiaofeng Zhu and Ning Xue
Micromachines 2019, 10(8), 497; https://doi.org/10.3390/mi10080497 - 26 Jul 2019
Cited by 8 | Viewed by 3209
Abstract
Atmospheric particulate matter (PM) air-microfluidic grading chip is the premise for realizing high-precision PM online monitoring. It can be used as an indispensable basis for identifying pollution sources and controlling inhalable harmful substances. In this paper, based on aerodynamic theory and COMSOL numerical [...] Read more.
Atmospheric particulate matter (PM) air-microfluidic grading chip is the premise for realizing high-precision PM online monitoring. It can be used as an indispensable basis for identifying pollution sources and controlling inhalable harmful substances. In this paper, based on aerodynamic theory and COMSOL numerical analysis, a two-stage PM air-microfluidic grading chip with cut-off diameters of 10 μm and 2.5 μm was designed. The effects of chip inlet width (W), main flow width (L), second channel width (S), and split ratio (Q1/Q) on PM classification efficiency were analyzed, and optimized design parameters were achieved. The collection efficiency curves were plotted according to PM separation effects of the chip on various particle sizes (0.5–15 μm). The results indicate that the chip has good separation effect, which provides an efficient structural model for the PM micro-fluidization chip design. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

18 pages, 7284 KiB  
Article
A Digital Calibration Technique of MEMS Gyroscope for Closed-Loop Mode-Matching Control
by Cheng Li, Bo Yang, Xin Guo and Lei Wu
Micromachines 2019, 10(8), 496; https://doi.org/10.3390/mi10080496 - 25 Jul 2019
Cited by 12 | Viewed by 3553
Abstract
A digital excitation-calibration technique of dual-mass MEMS gyroscope for closed-loop mode-matching control is presented in this paper. The technique, which takes advantage of the symmetrical amplitude response of MEMS gyroscope, exploits a two-side excitation signal to actuate the sense mode to obtain the [...] Read more.
A digital excitation-calibration technique of dual-mass MEMS gyroscope for closed-loop mode-matching control is presented in this paper. The technique, which takes advantage of the symmetrical amplitude response of MEMS gyroscope, exploits a two-side excitation signal to actuate the sense mode to obtain the corresponding DC tuning voltage. The structural characteristics of dual-mass decoupled MEMS gyroscope and the tuning principle of excitation-calibration technique are introduced firstly. Then, the scheme of digital excitation-calibration system for the real-time mode-matching control is presented. Simultaneously, open-loop analysis and closed-loop analysis are deduced, respectively, to analyze the sources of tuning error and system stability. To verify the validity of the scheme and theoretical analysis, the system model was established by SIMULINK. The simulation results are proved to be consistent with the theoretical analysis, verifying the feasibility of the digital excitation-calibration technique. The control algorithms of the system were implemented with a FPGA device. Experimental results demonstrate that digital excitation-calibration technique can realize mode-matching within 1 s. The prototype with real-time mode-matching control has a bias instability of 0.813 ∘ /h and an ARW (Angular Random Walk) of 0.0117 ∘ / h . Compared to the mode-mismatching condition, the bias instability and ARW are improved by 3.25 and 4.49 times respectively. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

9 pages, 4284 KiB  
Article
The Role of ALD-ZnO Seed Layers in the Growth of ZnO Nanorods for Hydrogen Sensing
by Yangming Lu, Chiafen Hsieh and Guanci Su
Micromachines 2019, 10(7), 491; https://doi.org/10.3390/mi10070491 - 23 Jul 2019
Cited by 9 | Viewed by 3479
Abstract
Hydrogen is one of the most important clean energy sources of the future. Because of its flammability, explosiveness, and flammability, it is important to develop a highly sensitive hydrogen sensor. Among many gas sensing materials, zinc oxide has excellent sensing properties and is [...] Read more.
Hydrogen is one of the most important clean energy sources of the future. Because of its flammability, explosiveness, and flammability, it is important to develop a highly sensitive hydrogen sensor. Among many gas sensing materials, zinc oxide has excellent sensing properties and is therefore attracting attention. Effectively reducing the resistance of sensing materials and increasing the surface area of materials is an important issue to increase the sensitivity of gas sensing. Zinc oxide seed layers were prepared by atomic layer deposition (ALD) to facilitate the subsequent hydrothermal growth of ZnO nanorods. The nanorods are used as highly sensitive materials for sensing hydrogen due to their inherent properties as oxide semiconductors and their very high surface areas. The low resistance value of ALD-ZnO helps to transport electrons when sensing hydrogen gas and improves the sensitivity of hydrogen sensors. The large surface area of ZnO nanorods also provides lots of sites of gas adsorption which also increases the sensitivity of the hydrogen sensor. Our experimental results show that perfect crystallinity helped to reduce the electrical resistance of ALD-ZnO films. High areal nucleation density and sufficient inter-rod space were determining factors for efficient hydrogen sensing. The sensitivity increased with increasing hydrogen temperature, from 1.03 at 225 °C, to 1.32 at 380 °C after sensing 100 s in 10,000 ppm of hydrogen. We discuss in detail the properties of electrical conductivity, point defects, and crystal quality of ALD-ZnO films and their probable effects on the sensitivity of hydrogen sensing. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

10 pages, 3953 KiB  
Article
Investigation of Surface Plasmon Resonance (SPR) in MoS2- and WS2-Protected Titanium Side-Polished Optical Fiber as a Humidity Sensor
by Rozalina Zakaria, Nur Aina’a Mardhiah Zainuddin, Tan Chee Leong, Rosnadiya Rosli, Muhammad Farid Rusdi, Sulaiman Wadi Harun and Iraj Sadegh Amiri
Micromachines 2019, 10(7), 465; https://doi.org/10.3390/mi10070465 - 11 Jul 2019
Cited by 27 | Viewed by 3866
Abstract
In this paper, we report the effects of a side-polished fiber (SPF) coated with titanium (Ti) films in different thicknesses, namely 5 nm, 13 nm, and 36 nm, protected by a thin layer of transition metal dichalcogenides (TMDCs) such as molybdenum disulfide (MoS [...] Read more.
In this paper, we report the effects of a side-polished fiber (SPF) coated with titanium (Ti) films in different thicknesses, namely 5 nm, 13 nm, and 36 nm, protected by a thin layer of transition metal dichalcogenides (TMDCs) such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2), which provide ultra-sensitive sensor-based surface plasmon resonance (SPR) covering from the visible to mid-infrared region. The SPF deposited with Ti exhibits strong evanescent field interaction with the MoS2 and WS2, and good optical absorption, hence resulting in high-sensitivity performance. Incremental increases in the thickness of the Ti layer contribute to the enhancement of the intensity of transmission with redshift and broad spectra. The findings show that the optimum thickness of Ti with 36 nm combined with MoS2 causes weak redshifts of the longitudinal localized surface plasmon resonance (LSPR) mode, while the same thickness of Ti with WS2 causes large blueshifts. The redshifts are possibly due to a reduced plasmon-coupling effect with the excitonic region of MoS2. The observed blueshifts of the LSPR peak position are possibly due to surface modification between WS2 and Ti. Changing the relative humidity from 58% to 88% only elicited a response in Ti/MoS2. Thus, MoS2 shows more sensitivity on 36-nm thickness of Ti compared with WS2. Therefore, the proposed fiber-optic sensor with integration of 2D materials is capable of measuring humidity in any environment. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

9 pages, 3027 KiB  
Article
A Resonant Pressure Sensor Based upon Electrostatically Comb Driven and Piezoresistively Sensed Lateral Resonators
by Xiaoqing Shi, Sen Zhang, Deyong Chen, Junbo Wang, Jian Chen, Bo Xie, Yulan Lu and Yadong Li
Micromachines 2019, 10(7), 460; https://doi.org/10.3390/mi10070460 - 08 Jul 2019
Cited by 11 | Viewed by 2941
Abstract
This study proposes a microfabricated resonant pressure sensor in which a pair of double-ended tuning forks were utilized as resonators where comb electrodes and single-crystal silicon-based piezoresistors were used for electrostatic excitation and piezoresistive detection, respectively. In operations, pressures under measurements deform the [...] Read more.
This study proposes a microfabricated resonant pressure sensor in which a pair of double-ended tuning forks were utilized as resonators where comb electrodes and single-crystal silicon-based piezoresistors were used for electrostatic excitation and piezoresistive detection, respectively. In operations, pressures under measurements deform the pressure-sensitive diaphragm to cause stress variations of two resonators distributed on the central and side positions of the pressure-sensitive diaphragm, where the corresponding changes of the intrinsic resonant frequencies are then captured piezoresistively. The developed resonant pressure sensors were fabricated based on MEMS with open-loop and closed-loop characterizations conducted. Key sensing parameters including quality factors, differential pressure/temperature sensitivities and fitting errors were quantified as higher than 17,000, 48.24 Hz/kPa, 0.15 Hz/°C and better than 0.01% F.S. (140 kpa), respectively. In comparison to previously reported resonant pressure sensors driven by parallel-plate electrodes, the developed sensor in this study is featured with a lower temperature sensitivity and a higher stability. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

8 pages, 2174 KiB  
Article
Improving Sensitivity of a Micro Inductive Sensor for Wear Debris Detection with Magnetic Powder Surrounded
by Liankun Liu, Liang Chen, Saijie Wang, Yi Yin, Dazhuang Liu, Sen Wu, Zhijian Liu and Xinxiang Pan
Micromachines 2019, 10(7), 440; https://doi.org/10.3390/mi10070440 - 01 Jul 2019
Cited by 18 | Viewed by 3003
Abstract
The inductive detection of wear debris in lubrication oil is an effective method to monitor the machine status. As the wear debris is usually micro scale, a micro inductive sensor is always used to detect them in research papers or high-tech products. However, [...] Read more.
The inductive detection of wear debris in lubrication oil is an effective method to monitor the machine status. As the wear debris is usually micro scale, a micro inductive sensor is always used to detect them in research papers or high-tech products. However, the improvement of detection sensitivity for micro inductive sensors is still a great challenge, especially for early wear debris of 20 μm or smaller diameter. This paper proposes a novel method to improve the detection sensitivity of a micro inductive sensor. Regarding the magnetic powder surrounding the sensor, the magnetic field in the core of the sensor where the wear debris pass through would be enhanced due to the increased relative permeability. Thus, the inductive signal would be improved and the detection sensitivity would be increased. It is found that the inductive signal would linearly increase with increasing the concentration of the magnetic powder and this enhancement would also be effective for wear debris of different sizes. In addition, the detection limit of the micro inductive sensor used in our experiment could be extended to 11 μm wear debris by the proposed method. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

16 pages, 15812 KiB  
Article
Analysis on Characteristics of ZnO Surface Acoustic Wave with and without Micro-Structures
by Huei-Yu Huang, Hsi-Jen Chiang, Ching-Zong Wu, Yi Lin and Yung-Kang Shen
Micromachines 2019, 10(7), 434; https://doi.org/10.3390/mi10070434 - 30 Jun 2019
Cited by 7 | Viewed by 2490
Abstract
In this paper, we fabricate a surface acoustic wave (SAW) device with micro-structures on a zinc oxide (ZnO) thin film and measure its signal response. The manufacturing processes of the SAW device include the fabrication of micro-structures of a SAW element and its [...] Read more.
In this paper, we fabricate a surface acoustic wave (SAW) device with micro-structures on a zinc oxide (ZnO) thin film and measure its signal response. The manufacturing processes of the SAW device include the fabrication of micro-structures of a SAW element and its interdigital transducer by silicon micro-machining and the fabrication of a thin film of ZnO by RF magnetron sputtering. We, then, measure the SAW properties. This research investigates the properties of sputtered thin films for various amounts of O2/(Ar + O2) using Zn and ZnO targets. Regardless of target, the growth rate of the ZnO thin film decreases as the oxygen content increases. When the SAW is sputtered ZnO thin film using 30% oxygen, the digital signal of the SAW has better performance. The measurement signal of the SAW with micro-structures is similar to that without micro-structures. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Graphical abstract

12 pages, 8813 KiB  
Article
Single Drive Multi-Axis Gyroscope with High Dynamic Range, High Linearity and Wide Bandwidth
by Faisal Iqbal, Hussamud Din and Byeungleul Lee
Micromachines 2019, 10(6), 410; https://doi.org/10.3390/mi10060410 - 20 Jun 2019
Cited by 17 | Viewed by 5212
Abstract
This paper presents the design, fabrication, and characterization of a highly sensitive, single drive multi-axis gyroscope. The multi-axis gyroscope allows for a wide bandwidth in all three axes (X, Y, Z) and exhibits high linearity. The fabricated multi-axis gyroscope was fabricated with a [...] Read more.
This paper presents the design, fabrication, and characterization of a highly sensitive, single drive multi-axis gyroscope. The multi-axis gyroscope allows for a wide bandwidth in all three axes (X, Y, Z) and exhibits high linearity. The fabricated multi-axis gyroscope was fabricated with a structural thickness of 30 µm and packaged at 100 mtorr using wafer level packaging. The fabricated multi-axis gyroscope has a small footprint of 1426 × 1426 µm2, making it one of the smallest multi-axis gyroscopes. A custom printed circuit board (PCB) was designed for the evaluation of the multi-axis gyroscope. The experimental results demonstrate that the gyroscope has a high sensitivity of 12.56   μ V / dps ,   17.13   μ V / dps and 25.79   μ V / dps in the roll (X-sense), pitch (Y-sense) and yaw (Z-sense) modes respectively. The scale-factor non-linearity of the gyroscope is less than 0.2 % for roll and pitch mode and 0.001 % for the yaw mode, in the full-scale range of ± 1500   deg / s . The multi-axis gyroscope demonstrates an angle random walk of 2.79   dps / Hz , 2.14   dps / Hz , and   1.42   dps / Hz , for the roll, pitch and yaw rate with the in-run bias stability 1.62   deg / s , 1.14   deg / s and 0.84   deg / s respectively. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Graphical abstract

22 pages, 13896 KiB  
Article
Research on the Disc Sensitive Structure of a Micro Optoelectromechanical System (MOEMS) Resonator Gyroscope
by Xiang Shen, Liye Zhao and Dunzhu Xia
Micromachines 2019, 10(4), 264; https://doi.org/10.3390/mi10040264 - 19 Apr 2019
Cited by 12 | Viewed by 3400 | Correction
Abstract
A micro optoelectromechanical system (MOEMS) resonator gyroscope based on a waveguide micro-ring resonator was proposed. This sensor was operated by measuring the shift of the transmission spectrum. Modal analysis was carried out for the disc sensitive structure of the MOEMS resonator gyroscope (MOEMS-RG). [...] Read more.
A micro optoelectromechanical system (MOEMS) resonator gyroscope based on a waveguide micro-ring resonator was proposed. This sensor was operated by measuring the shift of the transmission spectrum. Modal analysis was carried out for the disc sensitive structure of the MOEMS resonator gyroscope (MOEMS-RG). We deduced the equations between the equivalent stiffness and voltage of each tuning electrode and the modal parameters. A comprehensive investigation of the influences of the structure parameters on the sensitivity noise of the MOEMS-RG is presented in this paper. The mechanical sensitivity and transducer sensitivities of the MOEMS-RG, with varying structural parameters, are calculated based on the finite-element method. Frequency response test and the fiber optic spectrometer displacement test were implemented to verify the reliability of the model. Research results indicate that the resonant frequencies of the operating modes are tested to be 5768.407 Hz and 5771.116 Hz and the resonant wavelength change ΔX was 0.08 nm for 45° rotation angle. The resonant wavelength, which has a good linear response in working range, changes from −0.071 nm to 0.080 μm. The MOEMS-RG, with an optimized disc sensitive structure, can detect the deformation of the sensitive membrane effectively, and has a high sensitivity. This resonator shows very large meff, low f 0 , and very high Q. Therefore, this resonator can provide a small A R W B ( 0.09 ° / h ), which makes it a promising candidate for a low-cost, batch-fabricated, small size inertial-grade MOEMS gyroscope. The multi-objective optimization method could be expanded to include other objectives, constraints, or variables relevant to all kinds of gyroscopes or other microelectromechanical systems devices. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

12 pages, 4679 KiB  
Article
Multichannel Inductive Sensor Based on Phase Division Multiplexing for Wear Debris Detection
by Sen Wu, Zhijian Liu, Haichao Yuan, Kezhen Yu, Yuefeng Gao, Liankun Liu and Xinxiang Pan
Micromachines 2019, 10(4), 246; https://doi.org/10.3390/mi10040246 - 13 Apr 2019
Cited by 18 | Viewed by 3318
Abstract
Inductive wear debris sensor has been widely used in real time machine lubricant oil condition monitoring and fault forecasting. However, the small sensing zone, which is designed for high sensitivity, of the existing sensors leads to low throughput. In order to improve the [...] Read more.
Inductive wear debris sensor has been widely used in real time machine lubricant oil condition monitoring and fault forecasting. However, the small sensing zone, which is designed for high sensitivity, of the existing sensors leads to low throughput. In order to improve the throughput, a novel multichannel wear debris sensor that is based on phase division multiplexing is presented. By introducing the phase shift circuit into the system, multiple sensing coils could work at different initial phases. Multiple signals of sensing coils could be combined into one output without information loss. Synchronized sampling is used for data recording, and output signals of multiple sensing coils are extracted from the recorded data. A four-channel wear debris sensor system was designed to demonstrate our method. Subsequently, crosstalk analysis, pseudo-dynamic testing and dynamic testing were conducted to check the sensing system. Results show that signals of four sensing coils could be simultaneously detected and the detection limit for ferrous wear debris is 33 μm. Using the presented method, real time wear debris detection in multiple channels could be achieved without increasing the number of excitation source and data acquisition equipment. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

10 pages, 5847 KiB  
Article
A Decoupling Design with T-Shape Structure for the Aluminum Nitride Gyroscope
by Jian Yang, Chaowei Si, Guowei Han, Meng Zhang, Jin Ning, Yongmei Zhao, Fuhua Yang and Xiaodong Wang
Micromachines 2019, 10(4), 244; https://doi.org/10.3390/mi10040244 - 12 Apr 2019
Cited by 1 | Viewed by 2448
Abstract
This paper reports a novel design for the decoupling of microelectromechanical systems (MEMS) gyroscopes. The MEMS gyroscope is based on piezoelectric aluminum nitride (AlN) film, and the main structure is a mass hung by T-shape beams. A pair of parallel drive electrodes are [...] Read more.
This paper reports a novel design for the decoupling of microelectromechanical systems (MEMS) gyroscopes. The MEMS gyroscope is based on piezoelectric aluminum nitride (AlN) film, and the main structure is a mass hung by T-shape beams. A pair of parallel drive electrodes are symmetrically placed on the surface of the vertical bar for driving the oscillating mass. A serpentine sense electrode is placed on the lateral bar. When the gyroscope is oscillating in drive mode, charges with equal quantity and opposite sign will be polarized and distributed symmetrically along the lateral bar. These charges neutralize each other at the sense electrode. Therefore, no coupling signals can be detected from the sense electrode. This design can realize the decoupling between the drive mode and sense mode. In this work, the T-shape decoupled structure was designed as the key component of an AlN piezoelectric gyroscope and the whole structure was simulated by COMSOL Multiphysics 5.2a. The working principle of the decoupling is described in detail. Electrical properties were characterized by the dynamic signal analyzer. According to the test results, the drive mode and the sense mode are decoupled. The coefficient of orthogonal coupling is 1.55%. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

Review

Jump to: Research, Other

28 pages, 3634 KiB  
Review
2D Nanomaterial-Based Surface Plasmon Resonance Sensors for Biosensing Applications
by Sachin Singh, Pravin Kumar Singh, Ahmad Umar, Pooja Lohia, Hasan Albargi, L. Castañeda and D. K. Dwivedi
Micromachines 2020, 11(8), 779; https://doi.org/10.3390/mi11080779 - 15 Aug 2020
Cited by 78 | Viewed by 5215
Abstract
The absorption and binding energy of material plays an important role with a large surface area and conductivity for the development of any sensing device. The newly grown 2D nanomaterials like black phosphorus transition metal dichalcogenides (TMDCs) or graphene have excellent properties for [...] Read more.
The absorption and binding energy of material plays an important role with a large surface area and conductivity for the development of any sensing device. The newly grown 2D nanomaterials like black phosphorus transition metal dichalcogenides (TMDCs) or graphene have excellent properties for sensing devices’ fabrication. This paper summarizes the progress in the area of the 2D nanomaterial-based surface plasmon resonance (SPR) sensor during last decade. The paper also focuses on the structure of Kretschmann configuration, the sensing principle of SPR, its characteristic parameters, application in various fields, and some important recent works related to SPR sensors have also been discussed, based on the present and future scope of this field. The present paper provides a platform for researchers to work in the field of 2D nanomaterial-based SPR sensors. Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 1

Other

Jump to: Research, Review

2 pages, 3092 KiB  
Correction
Correction: Shen, X. et al. Research on the Disc Sensitive Structure of a Micro Optoelectromechanical System (MOEMS) Resonator Gyroscope. Micromachines, 2019, 10, 264
by Xiang Shen, Liye Zhao and Dunzhu Xia
Micromachines 2019, 10(5), 328; https://doi.org/10.3390/mi10050328 - 16 May 2019
Viewed by 2086
Abstract
In the published paper [...] Full article
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application, Volume II)
►▼ Show Figures

Figure 15

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-22
Back to TopTop