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Electronics, Volume 4, Issue 4 (December 2015) – 23 articles , Pages 723-1124

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1913 KiB  
Article
Equilibrium Molecular Dynamics (MD) Simulation Study of Thermal Conductivity of Graphene Nanoribbon: A Comparative Study on MD Potentials
by Asir Intisar Khan, Ishtiaque Ahmed Navid, Maliha Noshin, H. M. Ahsan Uddin, Fahim Ferdous Hossain and Samia Subrina
Electronics 2015, 4(4), 1109-1124; https://doi.org/10.3390/electronics4041109 - 21 Dec 2015
Cited by 61 | Viewed by 11222
Abstract
The thermal conductivity of graphene nanoribbons (GNRs) has been investigated using equilibrium molecular dynamics (EMD) simulation based on Green-Kubo (GK) method to compare two interatomic potentials namely optimized Tersoff and 2nd generation Reactive Empirical Bond Order (REBO). Our comparative study includes the estimation [...] Read more.
The thermal conductivity of graphene nanoribbons (GNRs) has been investigated using equilibrium molecular dynamics (EMD) simulation based on Green-Kubo (GK) method to compare two interatomic potentials namely optimized Tersoff and 2nd generation Reactive Empirical Bond Order (REBO). Our comparative study includes the estimation of thermal conductivity as a function of temperature, length and width of GNR for both the potentials. The thermal conductivity of graphene nanoribbon decreases with the increase of temperature. Quantum correction has been introduced for thermal conductivity as a function of temperature to include quantum effect below Debye temperature. Our results show that for temperatures up to Debye temperature, thermal conductivity increases, attains its peak and then falls off monotonically. Thermal conductivity is found to decrease with the increasing length for optimized Tersoff potential. However, thermal conductivity has been reported to increase with length using 2nd generation REBO potential for the GNRs of same size. Thermal conductivity, for the specified range of width, demonstrates an increasing trend with the increase of width for both the concerned potentials. In comparison with 2nd generation REBO potential, optimized Tersoff potential demonstrates a better modeling of thermal conductivity as well as provides a more appropriate description of phonon thermal transport in graphene nanoribbon. Such comparative study would provide a good insight for the optimization of the thermal conductivity of graphene nanoribbons under diverse conditions. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics - Prospects and Challenges)
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205 KiB  
Article
Dimensional Quantization and the Resonance Concept of the Low-Threshold Field Emission
by Georgy Fursey, Pavel Konorov, Boris Pavlov and Adil Yafyasov
Electronics 2015, 4(4), 1101-1108; https://doi.org/10.3390/electronics4041101 - 12 Dec 2015
Cited by 8 | Viewed by 3832
Abstract
We present a brief critical review of modern theoretical interpretations of the low-threshold field emission phenomenon for metallic electrodes covered with carbon structures, taking the latest experiments into consideration, and confirming the continuity of spectrum of resonance states localized on the interface of [...] Read more.
We present a brief critical review of modern theoretical interpretations of the low-threshold field emission phenomenon for metallic electrodes covered with carbon structures, taking the latest experiments into consideration, and confirming the continuity of spectrum of resonance states localized on the interface of the metallic body of the cathode and the carbon cover. Our proposal allowed us to interpret the double maxima of the emitted electron’s distribution on full energy. The theoretical interpretation is presented in a previous paper which describes the (1 + 1) model of a periodic 1D continuous interface. The overlapping of the double maxima may be interpreted taking into account a 2D superlattice periodic structure of the metal-vacuum interface, while the energy of emitted electrons lies on the overlapping spectral gaps of the interface 2D periodic lattice. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics - Prospects and Challenges)
477 KiB  
Article
Analysis of Deep Level Defects in GaN p-i-n Diodes after Beta Particle Irradiation
by Sofiane Belahsene, Noor Alhuda Al Saqri, Dler Jameel, Abdelmadjid Mesli, Anthony Martinez, Jacques De Sanoit, Abdallah Ougazzaden, Jean Paul Salvestrini, Abderrahim Ramdane and Mohamed Henini
Electronics 2015, 4(4), 1090-1100; https://doi.org/10.3390/electronics4041090 - 4 Dec 2015
Cited by 11 | Viewed by 6987
Abstract
The effect of beta particle irradiation (electron energy 0.54 MeV) on the electrical characteristics of GaN p-i-n diodes is investigated by current-voltage (I-V), capacitance-voltage (C-V) and deep-level transient spectroscopy (DLTS) measurements. The experimental studies show that, for the as-grown samples, three electron traps [...] Read more.
The effect of beta particle irradiation (electron energy 0.54 MeV) on the electrical characteristics of GaN p-i-n diodes is investigated by current-voltage (I-V), capacitance-voltage (C-V) and deep-level transient spectroscopy (DLTS) measurements. The experimental studies show that, for the as-grown samples, three electron traps are found with activation energies ranging from 0.06 to 0.81 eV and concentrations ranging from 1.2 × 1014 to 3.6 × 1015 cm−3, together with one hole trap with energy depth of 0.83 eV and concentration of 8 × 1014 cm−3. It has been found that the irradiation has no effect on these intrinsic defects. The irradiation affected only a shallow donor level close to Ec [0.06 eV-0.18 eV] on the p-side of the p-i-n junction. Full article
(This article belongs to the Special Issue Gallium Nitride Electronics)
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2550 KiB  
Article
Hardware/Software Co-Design of a Traffic Sign Recognition System Using Zynq FPGAs
by Yan Han, Kushal Virupakshappa, Esdras Vitor Silva Pinto and Erdal Oruklu
Electronics 2015, 4(4), 1062-1089; https://doi.org/10.3390/electronics4041062 - 4 Dec 2015
Cited by 19 | Viewed by 12739
Abstract
Traffic sign recognition (TSR), taken as an important component of an intelligent vehicle system, has been an emerging research topic in recent years. In this paper, a traffic sign detection system based on color segmentation, speeded-up robust features (SURF) detection and the k [...] Read more.
Traffic sign recognition (TSR), taken as an important component of an intelligent vehicle system, has been an emerging research topic in recent years. In this paper, a traffic sign detection system based on color segmentation, speeded-up robust features (SURF) detection and the k-nearest neighbor classifier is introduced. The proposed system benefits from the SURF detection algorithm, which achieves invariance to rotated, skewed and occluded signs. In addition to the accuracy and robustness issues, a TSR system should target a real-time implementation on an embedded system. Therefore, a hardware/software co-design architecture for a Zynq-7000 FPGA is presented as a major objective of this work. The sign detection operations are accelerated by programmable hardware logic that searches the potential candidates for sign classification. Sign recognition and classification uses a feature extraction and matching algorithm, which is implemented as a software component that runs on the embedded ARM CPU. Full article
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8575 KiB  
Review
Scalable Fabrication of 2D Semiconducting Crystals for Future Electronics
by Jiantong Li and Mikael Östling
Electronics 2015, 4(4), 1033-1061; https://doi.org/10.3390/electronics4041033 - 3 Dec 2015
Cited by 22 | Viewed by 11372
Abstract
Two-dimensional (2D) layered materials are anticipated to be promising for future electronics. However, their electronic applications are severely restricted by the availability of such materials with high quality and at a large scale. In this review, we introduce systematically versatile scalable synthesis techniques [...] Read more.
Two-dimensional (2D) layered materials are anticipated to be promising for future electronics. However, their electronic applications are severely restricted by the availability of such materials with high quality and at a large scale. In this review, we introduce systematically versatile scalable synthesis techniques in the literature for high-crystallinity large-area 2D semiconducting materials, especially transition metal dichalcogenides, and 2D material-based advanced structures, such as 2D alloys, 2D heterostructures and 2D material devices engineered at the wafer scale. Systematic comparison among different techniques is conducted with respect to device performance. The present status and the perspective for future electronics are discussed. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics - Prospects and Challenges)
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582 KiB  
Article
CDL, a Precise, Low-Cost Coincidence Detector Latch
by Ralf Joost and Ralf Salomon
Electronics 2015, 4(4), 1018-1032; https://doi.org/10.3390/electronics4041018 - 3 Dec 2015
Cited by 4 | Viewed by 6387
Abstract
The electronic detection of the coincidence of two events is still a key ingredient for high-performance applications, such as Positron Emission Tomography and Quantum Optics. Such applications are demanding, since the precision of their calculations and thus their conclusions directly depend on the [...] Read more.
The electronic detection of the coincidence of two events is still a key ingredient for high-performance applications, such as Positron Emission Tomography and Quantum Optics. Such applications are demanding, since the precision of their calculations and thus their conclusions directly depend on the duration of the interval in which two events are considered coincidental. This paper proposes a new circuitry, called coincidence detector latch (CDL), which is derived from standard RS latches. The CDL has the following advantages: low complexity, fully synthesizable, and high scalability. Even in its simple implementation, it achieves a coincidence window width as short as 115 ps, which is more than 10 times better than that reported by recent research. Full article
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2190 KiB  
Article
Runtime-Monitoring for Industrial Control Systems
by Helge Janicke, Andrew Nicholson, Stuart Webber and Antonio Cau
Electronics 2015, 4(4), 995-1017; https://doi.org/10.3390/electronics4040995 - 3 Dec 2015
Cited by 38 | Viewed by 7984
Abstract
Industrial Control Systems (ICS) are widely deployed in nation’s critical national infrastructures such as utilities, transport, banking and health-care. Whilst Supervisory Control and Data Acquisition (SCADA) systems are commonly deployed to monitor real-time data and operations taking place in the ICS they are [...] Read more.
Industrial Control Systems (ICS) are widely deployed in nation’s critical national infrastructures such as utilities, transport, banking and health-care. Whilst Supervisory Control and Data Acquisition (SCADA) systems are commonly deployed to monitor real-time data and operations taking place in the ICS they are typically not equipped to monitor the functional behaviour of individual components. In this paper (This paper expands on an earlier position paper presented at the International Symposium for Industrial Control System and SCADA Cyber Security Research 2014), we are presenting a runtime-monitoring technology that provides assurances of the functional behaviour of ICS components and demonstrates how this can be used to provide additional protection of the ICS against cyber attacks similar to the well-known Stuxnet attack. Full article
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2811 KiB  
Article
Narrow Bandwidth Top-Emitting OLEDs Designed for Rhodamine 6G Excitation in Biological Sensing Applications
by Matthias Jahnel, Beatrice Beyer, Michael Thomschke, Karsten Fehse, Felix Krujatz and Karl Leo
Electronics 2015, 4(4), 982-994; https://doi.org/10.3390/electronics4040982 - 25 Nov 2015
Cited by 11 | Viewed by 9192
Abstract
Organic light emitting diodes (OLED) are promising candidates offering in optical sensor applications to detect different gas compositions and excitable optical marker groups in chemical and biological processes. They enable attractive solutions for monitoring the gas phase composition of e.g., dissolved molecular oxygen [...] Read more.
Organic light emitting diodes (OLED) are promising candidates offering in optical sensor applications to detect different gas compositions and excitable optical marker groups in chemical and biological processes. They enable attractive solutions for monitoring the gas phase composition of e.g., dissolved molecular oxygen (O2) species in bio reactors or excitation of fluorescent markers. In this work, we investigate different OLED devices for biomedical applications to excite the fluorescent dye rhodamine 6G (R6G). The OLED devices are built in top emission geometry comprising a distributed Bragg reflector (DBR) acting as optical mirror. The OLED is optimized to provide a very narrow emission characteristic to excite the R6G at 530 nm wavelength and enabling the possibility to minimize the optical crosstalk between the OLED electroluminescence and the fluorescence of R6G. The DBR includes a thin film encapsulation and enables the narrowing of the spectral emission band depending on the number of DBR pairs. The comparison between optical simulation data and experimental results exhibits good agreement and proves process stability. Full article
(This article belongs to the Special Issue Organic Materials and Sensors for Biomedical Applications)
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142 KiB  
Editorial
Introduction to the Special Issue on Intelligent and Cooperative Vehicles
by Vicente Milanes
Electronics 2015, 4(4), 979-981; https://doi.org/10.3390/electronics4040979 - 24 Nov 2015
Cited by 1 | Viewed by 3305
Abstract
Intelligent vehicles constitute one of the hot research topics on the Intelligent Transportation Systems (ITS) field. The development of Advanced Driver Assistance Systems (ADAS) based on multi-fusion information coming from on-board cameras, lidar or radar sensors is leading to more sophisticated passive and [...] Read more.
Intelligent vehicles constitute one of the hot research topics on the Intelligent Transportation Systems (ITS) field. The development of Advanced Driver Assistance Systems (ADAS) based on multi-fusion information coming from on-board cameras, lidar or radar sensors is leading to more sophisticated passive and active safety systems. Additionally, the growing interest in using wireless communications to connect the vehicle either with other vehicles or the infrastructure is moving the intelligent vehicle research field toward smart interaction, moving to the Cooperative ITS (C-ITS) research field. [...] Full article
(This article belongs to the Special Issue Intelligent and Cooperative Vehicles)
283 KiB  
Article
Electrical Compact Modeling of Graphene Base Transistors
by Sébastien Frégonèse, Stefano Venica, Francesco Driussi and Thomas Zimmer
Electronics 2015, 4(4), 969-978; https://doi.org/10.3390/electronics4040969 - 18 Nov 2015
Cited by 9 | Viewed by 5503
Abstract
Following the recent development of the Graphene Base Transistor (GBT), a new electrical compact model for GBT devices is proposed. The transistor model includes the quantum capacitance model to obtain a self-consistent base potential. It also uses a versatile transfer current equation to [...] Read more.
Following the recent development of the Graphene Base Transistor (GBT), a new electrical compact model for GBT devices is proposed. The transistor model includes the quantum capacitance model to obtain a self-consistent base potential. It also uses a versatile transfer current equation to be compatible with the different possible GBT configurations and it account for high injection conditions thanks to a transit time based charge model. Finally, the developed large signal model has been implemented in Verilog-A code and can be used for simulation in a standard circuit design environment such as Cadence or ADS. This model has been verified using advanced numerical simulation. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics - Prospects and Challenges)
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2449 KiB  
Article
A Technique for Mitigating Thermal Stress and Extending Life Cycle of Power Electronic Converters Used for Wind Turbines
by Canras Batunlu and Alhussein Albarbar
Electronics 2015, 4(4), 947-968; https://doi.org/10.3390/electronics4040947 - 17 Nov 2015
Cited by 14 | Viewed by 7435
Abstract
Over the last two decades, various models have been developed to assess and improve the reliability of power electronic conversion systems (PECs) with a focus on those used for wind turbines. However, only few studies have dealt with mitigating the PECs thermo-mechanical effects [...] Read more.
Over the last two decades, various models have been developed to assess and improve the reliability of power electronic conversion systems (PECs) with a focus on those used for wind turbines. However, only few studies have dealt with mitigating the PECs thermo-mechanical effects on their reliability taking into account variations in wind characteristics. This work critically investigates this issue and attempts to offer a mitigating technique by, first, developing realistic full scale (FS) and partial scale (PS) induction generator models combined with two level back-to-back PECs. Subsequently, deriving a driving algorithm, which reduces PEC’s operating temperature by controlling its switching patterns. The developed switching procedure ensures minimum temperature fluctuations by adapting the variable DC link and system’s frequency of operation. It was found for both FS and PS topologies, that the generator side converters have higher mean junction temperatures where the grid side ones have more fluctuations on their thermal profile. The FS and PS cycling temperatures were reduced by 12 °C and 5 °C, respectively. Moreover, this led to a significant improvement in stress; approximately 27 MPa stress reduction for the FS induction generator PEC. Full article
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1452 KiB  
Review
Towards the Realization of Graphene Based Flexible Radio Frequency Receiver
by Maruthi N. Yogeesh, Kristen N. Parrish, Jongho Lee, Saungeun Park, Li Tao and Deji Akinwande
Electronics 2015, 4(4), 933-946; https://doi.org/10.3390/electronics4040933 - 11 Nov 2015
Cited by 11 | Viewed by 8406
Abstract
We report on our progress and development of high speed flexible graphene field effect transistors (GFETs) with high electron and hole mobilities (~3000 cm2/V·s), and intrinsic transit frequency in the microwave GHz regime. We also describe the design and fabrication of [...] Read more.
We report on our progress and development of high speed flexible graphene field effect transistors (GFETs) with high electron and hole mobilities (~3000 cm2/V·s), and intrinsic transit frequency in the microwave GHz regime. We also describe the design and fabrication of flexible graphene based radio frequency system. This RF communication system consists of graphite patch antenna at 2.4 GHz, graphene based frequency translation block (frequency doubler and AM demodulator) and graphene speaker. The communication blocks are utilized to demonstrate graphene based amplitude modulated (AM) radio receiver operating at 2.4 GHz. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics - Prospects and Challenges)
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283 KiB  
Communication
Usability of the Stylus Pen in Mobile Electronic Documentation
by Eunil Park, Angel P. Del Pobil and Sang Jib Kwon
Electronics 2015, 4(4), 922-932; https://doi.org/10.3390/electronics4040922 - 6 Nov 2015
Cited by 4 | Viewed by 9724
Abstract
Stylus pens are often used with mobile information devices. However, few studies have examined the stylus’ simple movements because the technical expertise to support documentation with stylus pens has not been developed. This study examined the usability of stylus pens in authentic documentation [...] Read more.
Stylus pens are often used with mobile information devices. However, few studies have examined the stylus’ simple movements because the technical expertise to support documentation with stylus pens has not been developed. This study examined the usability of stylus pens in authentic documentation tasks, including three main tasks (sentence, table, and paragraph making) with two types of styluses (touchsmart stylus and mobile stylus) and a traditional pen. The statistical results showed that participants preferred the traditional pen in all criteria. Because of inconvenient hand movements, the mobile stylus was the least preferred on every task. Mobility does not provide any advantage in using the stylus. In addition, the study also found inconvenient hand support using a stylus and different feedback between a stylus and a traditional pen. Full article
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812 KiB  
Article
Software-Controlled Next Generation Optical Circuit Switching for HPC and Cloud Computing Datacenters
by Muhammad Imran, Martin Collier, Pascal Landais and Kostas Katrinis
Electronics 2015, 4(4), 909-921; https://doi.org/10.3390/electronics4040909 - 5 Nov 2015
Cited by 1 | Viewed by 6399
Abstract
In this paper, we consider the performance of optical circuit switching (OCS) systems designed for data center networks by using network-level simulation. Recent proposals have used OCS in data center networks but the relatively slow switching times of OCS-MEMS switches (10–100 ms) and [...] Read more.
In this paper, we consider the performance of optical circuit switching (OCS) systems designed for data center networks by using network-level simulation. Recent proposals have used OCS in data center networks but the relatively slow switching times of OCS-MEMS switches (10–100 ms) and the latencies of control planes in these approaches have limited their use to the largest data center networks with workloads that last several seconds. Herein, we extend the applicability and generality of these studies by considering dynamically changing short-lived circuits in software-controlled OCS switches, using the faster switching technologies that are now available. The modelled switch architecture features fast optical switches in a single hop topology with a centralized, software-defined optical control plane. We model different workloads with various traffic aggregation parameters to investigate the performance of such designs across usage patterns. Our results show that, with suitable choices for the OCS system parameters, delay performance comparable to that of electrical data center networks can be obtained. Full article
(This article belongs to the Special Issue Software-Defined Optical Networks)
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1472 KiB  
Review
Organic Bioelectronic Tools for Biomedical Applications
by Susanne Löffler, Ben Libberton and Agneta Richter-Dahlfors
Electronics 2015, 4(4), 879-908; https://doi.org/10.3390/electronics4040879 - 5 Nov 2015
Cited by 42 | Viewed by 12484
Abstract
Organic bioelectronics forms the basis of conductive polymer tools with great potential for application in biomedical science and medicine. It is a rapidly growing field of both academic and industrial interest since conductive polymers bridge the gap between electronics and biology by being [...] Read more.
Organic bioelectronics forms the basis of conductive polymer tools with great potential for application in biomedical science and medicine. It is a rapidly growing field of both academic and industrial interest since conductive polymers bridge the gap between electronics and biology by being electronically and ionically conductive. This feature can be employed in numerous ways by choosing the right polyelectrolyte system and tuning its properties towards the intended application. This review highlights how active organic bioelectronic surfaces can be used to control cell attachment and release as well as to trigger cell signaling by means of electrical, chemical or mechanical actuation. Furthermore, we report on the unique properties of conductive polymers that make them outstanding materials for labeled or label-free biosensors. Techniques for electronically controlled ion transport in organic bioelectronic devices are introduced, and examples are provided to illustrate their use in self-regulated medical devices. Organic bioelectronics have great potential to become a primary platform in future bioelectronics. We therefore introduce current applications that will aid in the development of advanced in vitro systems for biomedical science and of automated systems for applications in neuroscience, cell biology and infection biology. Considering this broad spectrum of applications, organic bioelectronics could lead to timely detection of disease, and facilitate the use of remote and personalized medicine. As such, organic bioelectronics might contribute to efficient healthcare and reduced hospitalization times for patients. Full article
(This article belongs to the Special Issue Recent Advances in Organic Bioelectronics and Sensors)
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702 KiB  
Article
Dependable Control for Wireless Distributed Control Systems
by Michael Short, Fathi Abugchem and Usama Abrar
Electronics 2015, 4(4), 857-878; https://doi.org/10.3390/electronics4040857 - 2 Nov 2015
Cited by 7 | Viewed by 6266
Abstract
The use of wireless communications for real-time control applications poses several problems related to the comparatively low reliability of the communication channels. This paper is concerned with adaptive and predictive application-level strategies for ameliorating the effects of packet losses and burst errors in [...] Read more.
The use of wireless communications for real-time control applications poses several problems related to the comparatively low reliability of the communication channels. This paper is concerned with adaptive and predictive application-level strategies for ameliorating the effects of packet losses and burst errors in industrial sampled-data Distributed Control Systems (DCSs), which are implemented via one or more wireless and/or wired links, possibly spanning multiple hops. The paper describes an adaptive compensator that reconstructs the best estimates (in a least squares sense) of a sequence of one or more missing sensor node data packets in the controller node. At each sample time, the controller node calculates the current control, and a prediction of future controls to apply over a short time horizon; these controls are forwarded to the actuator node every sample time step. A simple design method for a digital Proportional Integral Derivative (PID)-like adaptive controller is also described for use in the controller node. Together these mechanisms give robustness to packet losses around the control loop; in addition, the majority of the computational overhead resides in the controller node. An implementation of the proposed techniques is applied to a case study using a Hardware in the Loop (HIL) test facility, and favorable results (in terms of both performance and computational overheads) are found when compared to an existing robust control method for a DCS experiencing artificially induced burst errors. Full article
(This article belongs to the Special Issue Wireless Sensor and Actuator Networks)
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3529 KiB  
Article
Enhanced Visibility of MoS2, MoSe2, WSe2 and Black-Phosphorus: Making Optical Identification of 2D Semiconductors Easier
by Gabino Rubio-Bollinger, Ruben Guerrero, David Perez De Lara, Jorge Quereda, Luis Vaquero-Garzon, Nicolas Agraït, Rudolf Bratschitsch and Andres Castellanos-Gomez
Electronics 2015, 4(4), 847-856; https://doi.org/10.3390/electronics4040847 - 28 Oct 2015
Cited by 43 | Viewed by 9236
Abstract
We explore the use of Si3N4/Si substrates as a substitute of the standard SiO2/Si substrates employed nowadays to fabricate nanodevices based on 2D materials. We systematically study the visibility of several 2D semiconducting materials that are attracting [...] Read more.
We explore the use of Si3N4/Si substrates as a substitute of the standard SiO2/Si substrates employed nowadays to fabricate nanodevices based on 2D materials. We systematically study the visibility of several 2D semiconducting materials that are attracting a great deal of interest in nanoelectronics and optoelectronics: MoS2, MoSe2, WSe2 and black-phosphorus. We find that the use of Si3N4/Si substrates provides an increase of the optical contrast up to a 50%–100% and also the maximum contrast shifts towards wavelength values optimal for human eye detection, making optical identification of 2D semiconductors easier. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics - Prospects and Challenges)
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5267 KiB  
Article
Electrical Reliability of a Film-Type Connection during Bending
by Ryosuke Mitsui, Junya Sato, Seiya Takahashi and Shin-ichiro Nakajima
Electronics 2015, 4(4), 827-846; https://doi.org/10.3390/electronics4040827 - 26 Oct 2015
Cited by 4 | Viewed by 7634
Abstract
With the escalating demands for downsizing and functionalizing mobile electronics, flexible electronics have become an important aspect of future technologies. To address limitations concerning junction deformation, we developed a new connection method using a film-type connector that is less than 0.1 mm thick. [...] Read more.
With the escalating demands for downsizing and functionalizing mobile electronics, flexible electronics have become an important aspect of future technologies. To address limitations concerning junction deformation, we developed a new connection method using a film-type connector that is less than 0.1 mm thick. The film-type connector is composed of an organic film substrate, a UV-curable adhesive that deforms elastically under pressure, and electrodes that are arranged on the adhesive. The film-type connection relies on a plate-to-plate contact, which ensures a sufficient contact area. The electrical reliability of the film-type connection was investigated based on changes in the resistance during bending at curvature radii of 70, 50, 25, 10, 5, and 2.5 mm. The connection was bent 1000 times to investigate the reproducibility of the connector’s bending properties. The tests showed that no disconnections occurred due to bending in the vertical direction of the electrode, but disconnections were observed due to bending in the parallel direction at curvature radii of 10, 5, and 2.5 mm. In addition, the maximum average change in resistance was less than 70 milliohms unless a disconnection was generated. These results support the application of the new film-type connection in future flexible devices. Full article
(This article belongs to the Special Issue Flexible Electronics)
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724 KiB  
Article
Time Delay Extraction from Frequency Domain Data Using Causal Fourier Continuations for High-Speed Interconnects
by Lyudmyla L. Barannyk, Hung H. Tran, Aicha Elshabini and Fred D. Barlow
Electronics 2015, 4(4), 799-826; https://doi.org/10.3390/electronics4040799 - 23 Oct 2015
Cited by 3 | Viewed by 4659
Abstract
We present a new method for time delay estimation using band limited frequency domain data representing the port responses of interconnect structures. The approach is based on the spectrally accurate method for causality characterization that employs SVD-based causal Fourier continuations, which was recently [...] Read more.
We present a new method for time delay estimation using band limited frequency domain data representing the port responses of interconnect structures. The approach is based on the spectrally accurate method for causality characterization that employs SVD-based causal Fourier continuations, which was recently developed by the authors. The time delay extraction is constructed by incorporating a linearly varying phase factor to the system of equations that determines the Fourier coefficients. The method is capable of determining the time delay using data affected by noise or approximation errors that come from measurements or numerical simulations. It can also be employed when only a limited number of frequency responses is available. The technique can be extended to multi-port and mixed-mode networks. Several analytical and simulated examples are used to demonstrate the accuracy and strength of the proposed technique. Full article
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293 KiB  
Article
Performance Analysis of Heterodyne-Detected OCDMA Systems Using PolSK Modulation over a Free-Space Optical Turbulence Channel
by Fan Bai, Yuwei Su and Takuro Sato
Electronics 2015, 4(4), 785-798; https://doi.org/10.3390/electronics4040785 - 16 Oct 2015
Cited by 4 | Viewed by 4913
Abstract
This paper presents a novel model of heterodyne-detected optical code-division multiple-access (OCDMA) systems employing polarization shift keying (PolSK) modulation over a free-space optical (FSO) turbulence channel. In this article, a new transceiver configuration and detailed analytical model for the proposed system are provided [...] Read more.
This paper presents a novel model of heterodyne-detected optical code-division multiple-access (OCDMA) systems employing polarization shift keying (PolSK) modulation over a free-space optical (FSO) turbulence channel. In this article, a new transceiver configuration and detailed analytical model for the proposed system are provided and discussed, taking into consideration the potential of heterodyne detection on mitigating the impact of turbulence-induced irradiance fluctuation on the performance of the proposed system under the gamma-gamma turbulence channel. Furthermore, we derived the closed-form expressions for the system error probability and outage probability, respectively. We determine the advantages of the proposed modeling by performing a comparison with a direct detection scheme obtained from an evaluation of link performance under the same environment conditions. The presented work also shows the most significant impact factor that degrades the performance of the proposed system and indicates that the proposed approach offers an optimum link performance compared to conventional cases. Full article
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142 KiB  
Review
Introduction to Hardware Security
by Yier Jin
Electronics 2015, 4(4), 763-784; https://doi.org/10.3390/electronics4040763 - 13 Oct 2015
Cited by 53 | Viewed by 13419
Abstract
Hardware security has become a hot topic recently with more and more researchers from related research domains joining this area. However, the understanding of hardware security is often mixed with cybersecurity and cryptography, especially cryptographic hardware. For the same reason, the research scope [...] Read more.
Hardware security has become a hot topic recently with more and more researchers from related research domains joining this area. However, the understanding of hardware security is often mixed with cybersecurity and cryptography, especially cryptographic hardware. For the same reason, the research scope of hardware security has never been clearly defined. To help researchers who have recently joined in this area better understand the challenges and tasks within the hardware security domain and to help both academia and industry investigate countermeasures and solutions to solve hardware security problems, we will introduce the key concepts of hardware security as well as its relations to related research topics in this survey paper. Emerging hardware security topics will also be clearly depicted through which the future trend will be elaborated, making this survey paper a good reference for the continuing research efforts in this area. Full article
1160 KiB  
Article
Reactive Planning of Autonomous Vehicles for Traffic Scenarios
by Rahul Kala and Kevin Warwick
Electronics 2015, 4(4), 739-762; https://doi.org/10.3390/electronics4040739 - 9 Oct 2015
Cited by 7 | Viewed by 5373
Abstract
Autonomous vehicles operate in real time traffic scenarios and aim to reach their destination from their source in the most efficient manner possible. Research in mobile robotics provides a variety of sophisticated means with which to plan the path of these vehicles. Conversely [...] Read more.
Autonomous vehicles operate in real time traffic scenarios and aim to reach their destination from their source in the most efficient manner possible. Research in mobile robotics provides a variety of sophisticated means with which to plan the path of these vehicles. Conversely professional human drivers usually drive using instinctive means, which enables them to reach their goal almost optimally whilst still obeying all traffic laws. In this paper we propose the use of fuzzy logic for novel motion planning. The planner is generated using an evolutionary algorithm which resembles the learning stage of professional drivers. Whether to overtake or not, is a decision which affects one’s driving and the decision is made using some deliberation. We further extend the approach to perform decision making regarding overtaking for all vehicles. Further we coordinate the motion of the vehicles at a traffic crossing to avoid any potential jam or collision. Experimental results prove that by using this approach we have been able to make the vehicles move in an optimal manner in a variety of scenarios. Full article
(This article belongs to the Special Issue Intelligent and Cooperative Vehicles)
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Article
Theoretical Analysis of Vibration Frequency of Graphene Sheets Used as Nanomechanical Mass Sensor
by Toshiaki Natsuki
Electronics 2015, 4(4), 723-738; https://doi.org/10.3390/electronics4040723 - 28 Sep 2015
Cited by 27 | Viewed by 5344
Abstract
Nanoelectromechanical resonator sensors based on graphene sheets (GS) show ultrahigh sensitivity to vibration. However, many factors such as the layer number and dimension of the GSs will affect the sensor characteristics. In this study, an analytical model is proposed to investigate the vibration [...] Read more.
Nanoelectromechanical resonator sensors based on graphene sheets (GS) show ultrahigh sensitivity to vibration. However, many factors such as the layer number and dimension of the GSs will affect the sensor characteristics. In this study, an analytical model is proposed to investigate the vibration behavior of double-layered graphene sheets (DLGSs) with attached nanoparticles. Based on nonlocal continuum mechanics, the influences of the layer number, dimensions of the GSs, and of the mass and position of nanoparticles attached to the GSs on the vibration response of GS resonators are discussed in detail. The results indicate that nanomasses can easily be detected by GS resonators, which can be used as a highly sensitive nanomechanical element in sensor systems. A logarithmically linear relationship exists between the frequency shift and the attached mass when the total mass attached to GS is less than about 1.0 zg. Accordingly, it is convenient to use a linear calibration for the calculation and determination of attached nanomasses. The simulation approach and the parametric investigation are useful tools for the design of graphene-based nanomass sensors and devices. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics - Prospects and Challenges)
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