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Micromachines
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Feature Papers of Micromachines in Engineering and Technology 2022
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Feature Papers of Micromachines in Engineering and Technology 2022

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

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 30183

Special Issue Editor

Prof. Dr. Stephen Edward Saddow

E-Mail Website
Guest Editor
Department of Electrical Engineering, University of South Florida, 4202 East Fowler Avenue, ENB118, Tampa, FL 33620, USA
Interests: SiC; neural interfaces; SiC MEMS; biotechnology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

We are pleased to announce the Special Issue entitled “Feature Papers of Micromachines in Engineering and Technology 2022”. In recent years, we have cooperated with many excellent scholars/scientific groups and published several very important high-level works that have already received numerous citations, according to Web of Science data. We aim to introduce new insights into the scientific developments and cutting-edge technology related to micromachines in the engineering and technology fields, which will make a great contribution to the community.

This Special Issue will be a collection of high-quality papers by outstanding scholars from around the world. Both original research articles and comprehensive review papers are welcome. The papers will be published with full open access after peer review to benefit both authors and readers.

You are welcome to send short proposals for submissions of Feature Papers to our Editorial Office ([email protected]) before submission. These will undergo a preliminary evaluation by our Editors. Please note that selected full papers will still be subjected to a thorough and rigorous peer review.

We look forward to receiving your excellent work.

Prof. Dr. Stephen Edward Saddow
Guest Editor

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.

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Published Papers (18 papers)

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Research

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8 pages, 2706 KiB  
Communication
Analytical and Physical Investigation on Source Resistance in InxGa1−xAs Quantum-Well High-Electron-Mobility Transistors
by Ji-Hoon Yoo, In-Geun Lee, Takuya Tsutsumi, Hiroki Sugiyama, Hideaki Matsuzaki, Jae-Hak Lee and Dae-Hyun Kim
Micromachines 2023, 14(2), 439; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14020439 - 12 Feb 2023
Cited by 2 | Viewed by 1262
Abstract
We present a fully analytical model and physical investigation on the source resistance (RS) in InxGa1−xAs quantum-well high-electron mobility transistors based on a three-layer TLM system. The RS model in this work was derived by [...] Read more.
We present a fully analytical model and physical investigation on the source resistance (RS) in InxGa1−xAs quantum-well high-electron mobility transistors based on a three-layer TLM system. The RS model in this work was derived by solving the coupled quadratic differential equations for each current component with appropriate boundary conditions, requiring only six physical and geometrical parameters, including ohmic contact resistivity (ρc), barrier tunneling resistivity (ρbarrier), sheet resistances of the cap and channel regions (Rsh_cap and Rsh_ch), side-recessed length (Lside) and gate-to-source length (Lgs). To extract each model parameter, we fabricated two different TLM structures, such as cap-TLM and recessed-TLM. The developed RS model in this work was in excellent agreement with the RS values measured from the two TLM devices and previously reported short-Lg HEMT devices. The findings in this work revealed that barrier tunneling resistivity already played a critical role in reducing the value of RS in state-of-the-art HEMTs. Unless the barrier tunneling resistivity is reduced considerably, innovative engineering on the ohmic contact characteristics and gate-to-source spacing would only marginally improve the device performance. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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12 pages, 2992 KiB  
Article
Basic Guide to Multilayer Microfluidic Fabrication with Polyimide Tape and Diode Laser
by Thana Thaweeskulchai and Albert Schulte
Micromachines 2023, 14(2), 324; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14020324 - 27 Jan 2023
Cited by 2 | Viewed by 1365
Abstract
For normal operations, microfluidic devices typically require an external source of pressure to deliver fluid flow through the microchannel. This requirement limits their use for benchtop research activities in a controlled static environment. To exploit the full potential of the miniaturization and portability [...] Read more.
For normal operations, microfluidic devices typically require an external source of pressure to deliver fluid flow through the microchannel. This requirement limits their use for benchtop research activities in a controlled static environment. To exploit the full potential of the miniaturization and portability of microfluidic platforms, passively driven capillary microfluidic devices have been developed to completely remove the need for an external pressure source. Capillary microfluidics can be designed to perform complex tasks by designing individual components of the device. These components, such as the stop valve and trigger valve, operate through changes in microchannel dimensions and aspect ratios. A direct, maskless fabrication protocol that allows the precise fabrication of microchannels and other microfluidic components is introduced here. A diode laser and polyimide tape on a PMMA substrate are the only components needed to start fabrication. By varying the laser power used and the number of laser repetitions, various depths and widths of the microchannel can be quickly created to meet specific needs. As an example of a functional unit, a trigger valve was fabricated and tested, as proof of the validity of the fabrication protocol. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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15 pages, 2532 KiB  
Article
Effects of Channel Length Scaling on the Electrical Characteristics of Multilayer MoS2 Field Effect Transistor
by Sreevatsan Radhakrishnan, Suggula Naga Sai Vishnu, Syed Ishtiyaq Ahmed and Rajagopalan Thiruvengadathan
Micromachines 2023, 14(2), 275; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14020275 - 20 Jan 2023
Viewed by 2501
Abstract
With the rapid miniaturization of integrated chips in recent decades, aggressive geometric scaling of transistor dimensions to nanometric scales has become imperative. Recent works have reported the usefulness of 2D transition metal dichalcogenides (TMDs) like MoS2 in MOSFET fabrication due to their [...] Read more.
With the rapid miniaturization of integrated chips in recent decades, aggressive geometric scaling of transistor dimensions to nanometric scales has become imperative. Recent works have reported the usefulness of 2D transition metal dichalcogenides (TMDs) like MoS2 in MOSFET fabrication due to their enhanced active surface area, thin body, and non-zero bandgap. However, a systematic study on the effects of geometric scaling down to sub-10-nm nodes on the performance of MoS2 MOSFETs is lacking. Here, the authors present an extensive study on the performance of MoS2 FETs when geometrically scaled down to the sub-10 nm range. Transport properties are modelled using drift-diffusion equations in the classical regime and self-consistent Schrödinger-Poisson solution using NEGF formulation in the quantum regime. By employing the device modeling tool COMSOL for the classical regime, drain current vs. gate voltage (ID vs. VGS) plots were simulated. On the other hand, NEGF formulation for quantum regions is performed using MATLAB, and transfer characteristics are obtained. The effects of scaling device dimensions, such as channel length and contact length, are evaluated based on transfer characteristics by computing performance metrics like drain-induced barrier lowering (DIBL), on-off currents, subthreshold swing, and threshold voltage. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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11 pages, 3333 KiB  
Article
Adhesion Evaluation of an Embedded SiN/GaAs Interface Using a Novel “Push-Out” Technique
by Sahar Dehkhoda, Mingyuan Lu and Han Huang
Micromachines 2023, 14(1), 37; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14010037 - 23 Dec 2022
Viewed by 1371
Abstract
Adhesion assessments of an embedded interface in a multilayer system that contains a ductile layer are challenging. The occurrence of plastic deformation in the ductile layer often leads to additional complexity in analysis. In this study, an innovative “push-out” technique was devised to [...] Read more.
Adhesion assessments of an embedded interface in a multilayer system that contains a ductile layer are challenging. The occurrence of plastic deformation in the ductile layer often leads to additional complexity in analysis. In this study, an innovative “push-out” technique was devised to evaluate the interfacial toughness (Gin) of the embedded SiN/GaAs interface in a Au/SiN/GaAs multilayer system. Focus ion beam (FIB) milling was utilized to manufacture the miniaturized specimen and scratching with a conical indenter was used to apply load. This approach effectively minimized plastic deformation in the soft Au layer while inducing tensile stress to the embedded SiN/GaAs interface. As a result, the Au/SiN bilayer detached from the GaAs substrate with little plasticity. The energy associated with the interfacial delamination was derived from analyzing the load–displacement curves obtained from the scratching test. The Gin of the SiN/GaAs interface was calculated by means of energy analysis, and the average Gin was 4.86 ± 0.96 J m−2. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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16 pages, 8235 KiB  
Article
Magnetic Harvester for an Autonomous Steel Health Monitoring System Based on Hall Effect Measurements
by Polychronis Pattakos, Spyridon Angelopoulos, Angelos Katsoulas, Aphrodite Ktena and Evangelos Hristoforou
Micromachines 2023, 14(1), 28; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14010028 - 23 Dec 2022
Cited by 1 | Viewed by 1019
Abstract
In this article, the construction and experimental behavior of an Internet of Things (IoT)-compatible steel health monitoring system are examined. Falling under the general category of nondestructive testing, this new sensor is combined with an energy harvester to produce an autonomous automated device [...] Read more.
In this article, the construction and experimental behavior of an Internet of Things (IoT)-compatible steel health monitoring system are examined. Falling under the general category of nondestructive testing, this new sensor is combined with an energy harvester to produce an autonomous automated device that can measure, store, and transmit measuring data without any need for human intervention. Based on common principles like the Hall effect, the monitoring system is put to use, and its results are presented. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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15 pages, 12228 KiB  
Article
Fabrication and Calibration of Pt-Rh10/Pt Thin-Film Thermocouple
by Fengxiang Wang, Zhenyu Lin, Zhijie Zhang, Yanfeng Li, Haoze Chen, Jiaqi Liu and Chao Li
Micromachines 2023, 14(1), 4; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14010004 - 20 Dec 2022
Cited by 4 | Viewed by 1659
Abstract
Aiming at the dynamic testing of the ignition temperature of micro-initiating explosives, a novel Pt-Rh10/Pt thin-film thermocouple was designed in this paper. The author carried out the preparation of the thermocouple by using a screen printing process on an Al2O3 [...] Read more.
Aiming at the dynamic testing of the ignition temperature of micro-initiating explosives, a novel Pt-Rh10/Pt thin-film thermocouple was designed in this paper. The author carried out the preparation of the thermocouple by using a screen printing process on an Al2O3 ceramic substrate. The formed thermocouple was made of Pt-Rh10 wire and Pt wire as compensation wires, with a size of ≤ 1 mm and a thickness of about 6 μm. In the testing process, the static calibration of the thermocouple at 50~600 °C and 650~1500 °C was completed by a portable temperature verification furnace and a horizontal high temperature verification furnace, and the results showed that the Seebeck coefficient of the thermocouple was about 10.70 μV/°C, and its output voltage–temperature curve was similar to that of a standard S-type thermocouple, which achieved the effective temperature measurement up to 1500 °C. The dynamic response of Pt-Rh10/Pt thin-film thermocouple was then tested and studied using the pulsed laser method, and the results show that the time constant of the thermocouple prepared in this paper is about 535 μs, which has the characteristics of fast response and high precision high-temperature testing. Compared with the traditional thin-film thermocouple, the thermocouple has excellent electrical conductivity, more oxidation resistance, the surface layer is not easy to peel off and other advantages. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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13 pages, 5081 KiB  
Article
Experimental Investigation on the Machinability Improvement in Magnetic-Field-Assisted Turning of Single-Crystal Copper
by Xian Wu, Yu Zhou, Congfu Fang, Laifa Zhu, Feng Jiang, Ke Sun, Yuan Li and Yiyang Lin
Micromachines 2022, 13(12), 2147; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13122147 - 04 Dec 2022
Cited by 4 | Viewed by 1347
Abstract
The single-point diamond-turning operation is a commonly used method for ultra-precision machining of various non-ferrous materials. In this paper, a magnetic field was introduced into a single-point diamond-turning system, and magnetic-field-assisted turning experiments were carried out. The results revealed that the magnetic field [...] Read more.
The single-point diamond-turning operation is a commonly used method for ultra-precision machining of various non-ferrous materials. In this paper, a magnetic field was introduced into a single-point diamond-turning system, and magnetic-field-assisted turning experiments were carried out. The results revealed that the magnetic field affects the metal-cutting process in the form of the cutting force, chip morphology, and surface quality. Compared with traditional turning, magnetic-field assisted turning increases the cutting force by 1.6 times, because of the additional induced Lorentz force, and reduces the cutting-force ratio and friction coefficient on the rake surface by 16%, with the improved tribological property of the tool/chip contact-interface. The chip morphology in the magnetic-field-assisted turning shows the smaller chip-compression ratio and the continuous side-morphology. With the magnetoplasticity effect of the metal material and the friction reduction, magnetic-field-assisted turning is helpful for improving metal machinability and achieving better surface-quality. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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8 pages, 4386 KiB  
Article
Tunable Gain SnS2/InSe Van der Waals Heterostructure Photodetector
by Seyedali Hosseini, Azam Iraji zad, Seyed Mohammad Mahdavi and Ali Esfandiar
Micromachines 2022, 13(12), 2068; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13122068 - 25 Nov 2022
Cited by 1 | Viewed by 1640
Abstract
Due to the favorable properties of two-dimensional materials such as SnS2, with an energy gap in the visible light spectrum, and InSe, with high electron mobility, the combination of them can create a novel platform for electronic and optical devices. Herein, we [...] Read more.
Due to the favorable properties of two-dimensional materials such as SnS2, with an energy gap in the visible light spectrum, and InSe, with high electron mobility, the combination of them can create a novel platform for electronic and optical devices. Herein, we study a tunable gain SnS2/InSe Van der Waals heterostructure photodetector. SnS2 crystals were synthesized by chemical vapor transport method and characterized using X-ray diffraction and Raman spectroscopy. The exfoliated SnS2 and InSe layers were transferred on the substrate. This photodetector presents photoresponsivity from 14 mA/W up to 740 mA/W and detectivity from 2.2 × 108 Jones up to 3.35 × 109 Jones by gate modulation from 0 V to +70 V. Light absorption and the charge carrier generation mechanism were studied by the Silvaco TCAD software and the results were confirmed by our experimental observations. The rather high responsivity and visible spectrum response makes the SnS2/InSe heterojunction a potential candidate for commercial visible image sensors. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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18 pages, 5273 KiB  
Article
A Cantilever-Based Piezoelectric MEMS for Arbitrary XY Path Generation
by Fabio Botta, Andrea Rossi and Nicola Pio Belfiore
Micromachines 2022, 13(9), 1514; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13091514 - 13 Sep 2022
Cited by 1 | Viewed by 1215
Abstract
This work pertains to the design of a cantilever-based piezoelectric MEMS device that is capable of generating arbitrary paths of its tip. The conceived device consists of a pair of rigidly coupled piezoelectric bimorph cantilevers, and a theoretical model is developed for the [...] Read more.
This work pertains to the design of a cantilever-based piezoelectric MEMS device that is capable of generating arbitrary paths of its tip. The conceived device consists of a pair of rigidly coupled piezoelectric bimorph cantilevers, and a theoretical model is developed for the analytical evaluation of the proper voltage distribution to be supplied to the inner and outer electrodes of each piezoelectric actuator, in order to drive the tip along any desired trajectory. Such a device could be appealing in some microsurgical operations, i.e., the unclogging of arteries, endoluminal treatment of obstructive lesions, but also as a 2D micropositioning stage, etc. Theoretical predictions of voltage versus time that allow several pathways such as circles, ellipses, spirals, etc., to be accomplished have been verified with multiphysics FEM simulations and the numerical outcomes seem to corroborate the proposed model. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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13 pages, 3710 KiB  
Article
Femtosecond Laser Fabrication of Microporous Membranes for Biological Applications
by Annalisa Volpe, Filippo Maria Conte Capodacqua, Valeria Garzarelli, Elisabetta Primiceri, Maria Serena Chiriacò, Caterina Gaudiuso, Francesco Ferrara and Antonio Ancona
Micromachines 2022, 13(9), 1371; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13091371 - 23 Aug 2022
Cited by 3 | Viewed by 1533
Abstract
The possibility of fabricating micrometric pore size membranes is gaining great interest in many applications, from studying cell signaling, to filtration. Currently, many technologies are reported to fabricate such microsystems, the choice of which depends strictly on the substrate material and on the [...] Read more.
The possibility of fabricating micrometric pore size membranes is gaining great interest in many applications, from studying cell signaling, to filtration. Currently, many technologies are reported to fabricate such microsystems, the choice of which depends strictly on the substrate material and on the final application. Here, we demonstrate the capability with a single femtosecond laser source and experimental setup to fabricate micromembranes both on polymeric and multilayer metallic substrate, without the need for moulds, mask, and complex facilities. In particular, the flexibility of laser drilling was exploited to obtain microfilters with pore size of 8 and 18 µm in diameter, on metallic and polymeric substrate, respectively, and controlled distribution. For evaluating the possibility to use such laser-fabricated membranes into biological assay, their biocompatibility has been investigated. To this aim, as a proof of concept, we tested the two materials into viability tests. The culture of mammalian cells on these microfabricated membranes were studied showing their compatibility with cells. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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12 pages, 5350 KiB  
Article
Silicon-on-Insulator Optical Waveguide Pressure Sensor Based on Mach-Zehnder Interferometer
by Chen Li, Chi Zhang, Lijun Yang and Fangtong Guo
Micromachines 2022, 13(8), 1321; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13081321 - 15 Aug 2022
Cited by 1 | Viewed by 1402
Abstract
At present, there are few methods to measure optical pressure using MEMS. However, due to its high precision and fast response, a ridge waveguide pressure sensor based on a Mach–Zehnder interferometer is designed in this paper. Through the design and optimization of each [...] Read more.
At present, there are few methods to measure optical pressure using MEMS. However, due to its high precision and fast response, a ridge waveguide pressure sensor based on a Mach–Zehnder interferometer is designed in this paper. Through the design and optimization of each component of the structure, the sensitivity of the pressure sensor was 2.2 × 10−3 W/kPa and the linearity was 5.9 × 10−3. The sensor had a good performance and small volume, which can be used in the field of light pressure measurement and other fields that required the measurement small pressures, such as the biomedicine field. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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20 pages, 3054 KiB  
Article
Dynamical Design and Gain Performance Analysis of a 3-DoF Micro-Gyro with an Anchored Leverage Mechanism
by Kunpeng Zhang, Sai Wang, Shuying Hao, Qichang Zhang and Jingjing Feng
Micromachines 2022, 13(8), 1201; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13081201 - 28 Jul 2022
Viewed by 1042
Abstract
In this paper, we apply the leverage amplification principle to improve the gain of a three-degrees-of-freedom (3-DoF) micro-gyro. The gain of the micro-gyro can be improved by designing linear and nonlinear micro-gyros with an anchored lever mechanism (ALM). First, the sensor system of [...] Read more.
In this paper, we apply the leverage amplification principle to improve the gain of a three-degrees-of-freedom (3-DoF) micro-gyro. The gain of the micro-gyro can be improved by designing linear and nonlinear micro-gyros with an anchored lever mechanism (ALM). First, the sensor system of the micro-gyro is designed as a complete 2-DOF system with an ALM. The effect of the leverage rate (LR) on the mass ratio and frequency coupling parameter (FCP) of the complete 2-DOF sense system is studied. We analyze the variation rule of the gain of the lever’s input and output as the LR increases. Afterwards, the bandwidth and gain performance of linear and nonlinear micro-gyros with an ALM is investigated by applying the arbitrarily tunable characteristics of peak spacing of the complete 2-DOF system. The influence of LR, FCP, nonlinear strength, damping, and peak spacing on bandwidth and gain of the 3-DOF micro-gyro is analyzed. The results indicate that both LR and FCP have a large effect on the gain and bandwidth of a micro-gyro with an ALM. The LR parameter mainly improves the gain of the micro-gyro, and the FCP parameter mainly adjusts the bandwidth performance. Adding levers can effectively improve the gain performance of the linear micro-gyro. The linear micro-gyro with an ALM can improve the gain by 4.5 dB compared to the one without an ALM. The nonlinear micro-gyro with an ALM combines two characteristics: the nonlinear micro-gyro can improve the bandwidth, while the lever structure can improve the gain. Compared with the linear micro-gyro without an ALM, the gain can be increased by 17.6 dB, and the bandwidth can be improved as well. In addition, the bandwidth of a micro-gyro with an ALM is related to the gain difference between the peaks of the lever output. The increase in the gain difference leads to a flattening of the left peak, which effectively broadens the bandwidth. For nonlinear micro-gyros with an ALM, the bandwidth can be further improved by increasing the nonlinear stiffness coefficient, and better gain and bandwidth can be obtained using a vacuum package. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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12 pages, 1420 KiB  
Article
A Technique for Rapid Bacterial-Density Enumeration through Membrane Filtration and Differential Pressure Measurements
by Xinhui Shen, Ting Wei Teo, Tian Fook Kong and Marcos
Micromachines 2022, 13(8), 1198; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13081198 - 28 Jul 2022
Viewed by 1695
Abstract
In this article, we present a microfluidic technique for the rapid enumeration of bacterial density with a syringe filter to trap bacteria and the quantification of the bacterial density through pressure difference measurement across the membrane. First, we established the baseline differential pressure [...] Read more.
In this article, we present a microfluidic technique for the rapid enumeration of bacterial density with a syringe filter to trap bacteria and the quantification of the bacterial density through pressure difference measurement across the membrane. First, we established the baseline differential pressure and hydraulic resistance for a filtration membrane by fully wetting the filter with DI water. Subsequently, when bacteria were infused and trapped at the pores of the membrane, the differential pressure and hydraulic resistance also increased. We characterized the infusion time required for the bacterial sample to achieve a normalized hydraulic resistance of 1.5. An equivalent electric-circuit model and calibration data sets from parametric studies were used to determine the general form of a calibration curve for the prediction of the bacterial density of a bacterial sample. As a proof of concept, we demonstrated through blind tests with Escherichia coli that the device is capable of determining the bacterial density of a sample ranging from 7.3 × 106 to 2.2 × 108 CFU/mL with mean and median accuracies of 87.21% and 91.33%, respectively. The sample-to-result time is 19 min for a sample with lower detection threshold, while for higher-bacterial-density samples the measurement time is further shortened to merely 8 min. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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9 pages, 2707 KiB  
Article
Linear and Nonlinear Optical Properties of a Doubly Clamped Suspended Monolayer Graphene Nanoribbon Nanoresonator
by Spyridon G. Kosionis and Emmanuel Paspalakis
Micromachines 2022, 13(8), 1179; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13081179 - 26 Jul 2022
Cited by 2 | Viewed by 1222
Abstract
We studied the optical properties of a hybrid structure that was composed of a semiconductor quantum dot and a doubly clamped suspended graphene nanoribbon nanoresonator. We obtained analytical results for the linear and third-order optical susceptibilities of the hybrid system. The spectrum of [...] Read more.
We studied the optical properties of a hybrid structure that was composed of a semiconductor quantum dot and a doubly clamped suspended graphene nanoribbon nanoresonator. We obtained analytical results for the linear and third-order optical susceptibilities of the hybrid system. The spectrum of the linear susceptibility exhibited a single resonance, and its position depended on the value of the on-resonance exciton energy and the exciton–nanoribbon resonator coupling strength coefficient; the amplitude of the resonance was independent of the values of these parameters. The third-order optical susceptibility spectrum exhibited a sharp resonance arising at low frequencies of the probe field, the position of which depended only on the frequency of the fundamental flexural phonon mode. It also presented a broader resonance arising at higher frequencies of the probe field, the position of which was determined both by the coupling strength coefficient and by the exciton frequency; its amplitude depended solely on the exciton–photon coupling strength. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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29 pages, 3635 KiB  
Article
Analytical Modeling of a New Compliant Microsystem for Atherectomy Operations
by Pietro Ursi, Andrea Rossi, Fabio Botta and Nicola Pio Belfiore
Micromachines 2022, 13(7), 1094; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13071094 - 11 Jul 2022
Cited by 5 | Viewed by 1412
Abstract
This work offers a new alternative tool for atherectomy operations, with the purpose of minimizing the risks for the patients and maximizing the number of clinical cases for which the system can be used, thanks to the possibility of scaling its size down [...] Read more.
This work offers a new alternative tool for atherectomy operations, with the purpose of minimizing the risks for the patients and maximizing the number of clinical cases for which the system can be used, thanks to the possibility of scaling its size down to lumen reduced to a few tenths of mm. The development of this microsystem has presented a certain theoretical work during the kinematic synthesis and the design stages. In the first stage a new multi-loop mechanism with a Stephenson’s kinematic chain (KC) was found and then adopted as the so-called pseudo-rigid body mechanism (PRBM). Analytical modeling was necessary to verify the synthesis requirements. In the second stage, the joint replacement method was applied to the PRBM to obtain a corresponding and equivalent compliant mechanism with lumped compliance. The latter presents two loops and six elastic joints and so the evaluation of the microsystem mechanical advantage (MA) had to be calculated by taking into account the accumulation of elastic energy in the elastic joints. Hence, a new closed form expression of the microsystem MA was found with a method that presents some new aspects in the approach. The results obtained with Finite Element Analysis (FEA) were compared to those obtained with the analytical model. Finally, it is worth noting that a microsystem prototype can be fabricated by using MEMS Technology classical methods, while the microsystem packaging could be a further development for the present investigation. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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9 pages, 1953 KiB  
Article
Vacuum Inner Spacer to Improve Annealing Effect during Electro-Thermal Annealing of Nanosheet FETs
by Dong-Hyun Wang, Khwang-Sun Lee and Jun-Young Park
Micromachines 2022, 13(7), 987; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13070987 - 24 Jun 2022
Viewed by 1618
Abstract
Electro-thermal annealing (ETA) in a MOSFET utilizes Joule heating. The high-temperature heat effectively cures gate dielectric damages induced by electrical stresses or ionizing radiation. However, even though ETA can be used to improve the reliability of logic and memory devices, applying ETA in [...] Read more.
Electro-thermal annealing (ETA) in a MOSFET utilizes Joule heating. The high-temperature heat effectively cures gate dielectric damages induced by electrical stresses or ionizing radiation. However, even though ETA can be used to improve the reliability of logic and memory devices, applying ETA in state-of-the-art field-effect transistors (FETs) such as nanosheet FETs (NS FETs) has not yet been demonstrated. This paper addresses the heat distribution characteristic of an NS FET considering the application of ETA, using 3D simulations. A vacuum inner spacer is newly proposed to improve annealing effects during ETA. In addition, evaluations of the device scaling and annealing effect were performed with respect to gate length, nanosheet-to-nanosheet vertical space, and inner spacer thickness. Guidelines for ETA in NS FETs can be provided on the basis of the results. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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Review

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33 pages, 7845 KiB  
Review
A Review of Circularly Polarized Dielectric Resonator Antennas: Recent Developments and Applications
by Nur Akmal Abd Rahman, Mohd Najib Mohd Yasin, Imran Mohd Ibrahim, Muzammil Jusoh, Shehab Khan Noor, Mervin Retnadhas Ekscalin Emalda Mary, Norshuhani Zamin and Nurhayati Nurhayati
Micromachines 2022, 13(12), 2178; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13122178 - 08 Dec 2022
Cited by 4 | Viewed by 2743
Abstract
A comprehensive review on recent developments and applications of circularly polarized (CP) dielectric resonator antennas (DRAs) is proposed in this paper. DRAs have received more considerations in various applications due to their advantages such as wide bandwidth, high gain, high efficiency, low losses, [...] Read more.
A comprehensive review on recent developments and applications of circularly polarized (CP) dielectric resonator antennas (DRAs) is proposed in this paper. DRAs have received more considerations in various applications due to their advantages such as wide bandwidth, high gain, high efficiency, low losses, and low profile. A broad justification for circular polarization and DRAs is stated at the beginning of the review. Various techniques such as single feed, dual, or multiple feeds used by different researchers for generating circular polarization in DRAs are briefly studied in this paper. Multiple-input-multiple-output (MIMO) CP DRAs, which can increase channel capacity, link reliability, and data rate, have also been analyzed. Additionally, innovative design solutions for broadening the circular polarization bandwidth and reducing mutual coupling are studied. Several applications of DRA are also discussed comprehensively. This paper finishes with concluding remarks. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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16 pages, 2347 KiB  
Review
A Review on Gel Polymer Electrolytes for Dye-Sensitized Solar Cells
by Prasad Raut, Vinay Kishnani, Kunal Mondal, Ankur Gupta and Sadhan C. Jana
Micromachines 2022, 13(5), 680; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13050680 - 27 Apr 2022
Cited by 13 | Viewed by 2983
Abstract
Significant growth has been observed in the research domain of dye-sensitized solar cells (DSSCs) due to the simplicity in its manufacturing, low cost, and high-energy conversion efficiency. The electrolytes in DSSCs play an important role in determining the photovoltaic performance of the DSSCs, [...] Read more.
Significant growth has been observed in the research domain of dye-sensitized solar cells (DSSCs) due to the simplicity in its manufacturing, low cost, and high-energy conversion efficiency. The electrolytes in DSSCs play an important role in determining the photovoltaic performance of the DSSCs, e.g., volatile liquid electrolytes suffer from poor thermal stability. Although low volatility liquid electrolytes and solid polymer electrolytes circumvent the stability issues, gel polymer electrolytes with high ionic conductivity and enduring stability are stimulating substitutes for liquid electrolytes in DSSC. In this review paper, the advantages of gel polymer electrolytes (GPEs) are discussed along with other types of electrolytes, e.g., solid polymer electrolytes and p-type semiconductor-based electrolytes. The benefits of incorporating ionic liquids into GPEs are highlighted in conjunction with the factors that affect the ionic conductivity of GPEs. The strategies on the improvement of the properties of DSSCs based on GPE are also presented. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in Engineering and Technology 2022)
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