In this work, sol—gel dip-coating technique was used to elaborate ZnO pure and ZnO/Al films. The impact of Al-doped concentration on the structural, optical, surface morphological and electrical properties of the elaborated samples was investigated. It was found that better electrical and optical performances have been obtained for an Al concentration equal to 5%, where the ZnO thin films exhibit a resistivity value equal to 1.64104 Ωcm. Moreover, highest transparency has been recorded for the same Al concentration value. The obtained results from this investigation make the developed thin film structure a potential candidate for high optoelectronic performance applications.

This article deals with the study of a new swimming microrobot behavior using an analytical investigation. The analyzed microrobot is associated by a spherical head and hybrid tail. The principle of modeling is based on solving of the coupled elastic/fluidic problems between the hybrid tail’s deflections and the running environment. In spite of the resulting nonlinear model can be exploited to enhance both the sailing ability and also can be controlled in viscous environment using nonlinear control investigations. The applications of the micro-robot have required the precision of control for targeting the running area in terms of response time and tracking error. Due to these limitations, the Flatness-ANFIS based control is used to ensure a good control behavior in hazardous environment. Our control investigation is coupled the differential flatness and adaptive neuro-fuzzy inference techniques, in which the flatness is used to planning the optimal trajectory and eliminate the nonlinearity effects of the resulting model. In other hand, the neuro-fuzzy inference technique is used to build the law of control technique and minimize the dynamic error of tracking trajectory. In particular, we deduct from a non linear model to an optimal model of the design parameter’s using Multi-Objective genetic algorithms (MOGAs). In addition, Computational fluid dynamics modeling of the microrobot is also carried out to study the produced thrust and velocity of the microrobot displacement taking into account the fluid parameters. Our analytical results have been validated by the recorded good agreement between the numerical and analytical results.

In this study, single crystal Ge layers have been deposited by molecular beam epitaxy on PSi substrate, with different thicknesses (40 nm and 80 nm) at the growth temperature of 400°C. Raman and Atomic force microscopy (AFM) have been applied for investigation of structural and morphological properties in order to explain the photoluminescence properties of the Ge on PSi layers. The results show a stronger Raman intensity of PSi due to change of its optical constant. Similarly, the Si/Ge/PSi sample shows a peak at 399 cm^-1 but with lower intensity compared with that of PSi probably due to the Si emission partially covered by the Ge inside the porous. Besides that, a sharp Raman peak at 298 cm^-1 is observed which reflects Raman active transverse optical mode of the introduced Ge which indicate the growth of Ge with good crystallinity. AFM characterization shows the rough silicon surface which can be regarded as a condensation point for small skeleton clusters to form, with different size of pores. These changes are highly responsible for its photoluminescence in the red wavelength range. This study explores the applicability of prepared Ge/PSi layers for its various applications in advanced optoelectronics field and silicon-on-insulator applications.

Single crystal Silicon (Si) layers have been deposited by molecular beam epitaxy on double-layer porous silicon (PSi). We investigate the structure and morphology of double-layer PSi as fabricated and after annealing at high temperature. We show that a top thin layer with a low porosity is used as a seed layer for epitaxial growth. While, the underlying higher porosity layer is used as an easily detectable etch stop layer. The morphology and structure of epitaxial Si layer grown on the double-layer PSi are investigated by transmission electron microscopy and high resolution X-ray diffraction. The results show that, an epitaxial Si layer with a low defect density can be grown. Epitaxial growth of thin crystalline layers on double-layer PSi can provide opportunities for silicon-on-insulator applications and Si-based solar cells provided that the epitaxial layer has a sufficient crystallographic quality.

Multi-Gate Junctionless MOSFETs are promising devices to overcome the undesired short channel effects for low cost nanoelectronic applications. However, the high series resistance associated to the source and drain extensions can arise as a serious problem when dealing with uniformly doped channel, which leads to the degradation of the device performance. Therefore, in order to obtain a global view of Double-Gate Junctionless (DGJ) MOSFET performance under critical conditions, new designs and models of nanoscale DGJ MOSFET including analog performance are important for the comprehension of the fundamentals of such device characteristics. In the present paper, a numerical investigation for the drain current and small signal characteristics is conducted for the DGJ MOSFET by including highly doped extension regions. The proposed approach, which is from a practical viewpoint a feasible technique by introducing only one ion implantation step, provides a good solution to improve the drain current, small signal parameters, analog/RF behavior and linearity of DGJ MOSFET for high performance analog applications. In this context, I–V and analog characteristics of the proposed design are investigated by 2-D numerical modeling and compared with conventional DGJ MOSFET characteristics.

In this paper, we propose a new optically controlled field effect transistor, OC-FET, based on both surface texturization and graded gate doping engineering. The proposed design consists of a gate with both graded doping and surface texturization aspects to ensure high efficient light absorption and low dark current, respectively. Moreover, using an analytical investigation, an overall performance comparison of the proposed dual texturized gate (DTG) OC-FET device and conventional OC-FETs has been studied in order to confirm the enhanced optical and electrical performance of the proposed design in terms of increased photoresponsivity (R), optical gain (Formula presented.) ratio, drain current driving capability (Formula presented.) and high signal to noise ratio. Simulations show very good agreement between the results of the developed analytical models and those of TCAD software for wide range of design parameters. The developed analytical models are used to formulate the objective functions to optimize the device performance using a multi-objective genetic algorithm (MOGA). The proposed MOGA-based approach is used to search the optimal design parameters, for which the electrical and optical device performance is maximized. The obtained superior electrical performance suggests that our DTG OC-FET offers great promise as optical sensors and transducers for CMOS-based optical communications.

In this paper, an optimized ultra-low power phototransistor design based on gradual gate doping engineering is proposed. Using an analytical investigation and numerical simulation, an overall performance comparison of the proposed phototransistor design and conventional structure has been studied, in order to show the improved characteristics provided by the proposed design in terms of increased \(I_{ON}/I_{OFF}\) ratio and superior photoresponsivity capability. The results obtained from our analytical investigation are validated by comparison with the numerical simulations, thus establishing the accuracy of our analytical investigation. Moreover, the developed analytical models are used to optimize the proposed design using a genetic algorithm (GA) based-computation. The advantages offered by the proposed design suggest the possibility to overcome the most challenging problem with the power requirements of the optical interconnect: power consumption in the light emitter and in the receiver. In this context, the proposed phototransistor owing to the high responsivity requires less optical power from the light emitter to achieve an acceptable signal-to-noise ratio compared to the phototransistor with conventional design.

In this paper, a new TiO₂-based UV photodetector including back triangular texturization morphology has been investigated numerically using accurate solutions of Maxwell’s equations. A quantitative study of the device optical parameters like responsivity, sensitivity, detectivity, derived current capability and signal to noise ratio have been carried out in order to review the device overall optical performance for UV optical communication applications. Based on the obtained results, we have found that the device performance figures-of-merit (FoMs) governing the optical behavior is strongly improved as compared to its conventional planar counterpart, where the proposed design offers superior photocurrent, higher responsivity and sensitivity in comparison with those provided by the planar structure. These results led us to suggest the optimization of the proposed morphology using genetic algorithm (GA), in order to improve the electric field confinement and UV-light trapping in TiO₂ absorber layer, where excellent ability has been recorded in enhancing the device absorbance. In this context, photodetector with optimized triangular texturization exhibits a 432% improvement, in term of responsivity, over planar structures and 120% improvement over the textured device without optimization. Thus, these encouraging results make the proposed device an extremely efficient candidate for high performance optoelectronic applications.

In this paper, the impact of the surface-textured front glass on the absorption of TiO ₂ /glass thin-film ultraviolet (UV) photodetector is investigated, in order to achieve the dual role of increasing the scattering of UV-light as well as reducing the refracting UV-light in the glass. The efficient control of these phenomena may lead to more electric field confinement and UV-light trapping in TiO ₂ absorber layer. Moreover, semianalytical modeling combined with particle swarm optimization is carried out for studying and enhancing the metal-semiconductor-metal photodetector optical and electrical performances. The results obtained from our semianalytical investigation are validated by comparison with the experimental data. It is found that the absorbance increases significantly by about 51% in optimized design over the planar structure, which is expected to improve the photodetector figures of merit. In this context, photodetector with optimized grooves texturization exhibits a 341% improvement, in terms of responsivity, in comparison with the planar structure and 275% improvement with respect to the textured device without optimization. The obtained results make the proposed design methodology a promising alternative for high-performance optoelectronic applications.

The influence of gate dielectric materials on the performance of a carbon nanotube field-effect transistor has been studied by a numerical simulation model. This model is based on a two-dimensional nonequilibrium Green’s function formalism performed with the self-consistent solution of the Poisson and Schrödinger equations. The device performance is investigated in terms of leakage current, on-state current, ION/IOFF" id="MathJax-Element-1-Frame" role="presentation" style="position:relative;" tabindex="0">ION/IOFF current ratio, subthreshold slope, drain-induced barrier lowering, as well as transconductance, drain conductance, and intrinsic gate delay. This study is carried out over a wide range of dielectric permittivities at low temperatures ranging from room temperature down to 100 K.

In this paper, new sensors based on a double-gate (DG) graphene nanoribbon field-effect transistor (GNRFET), for high-performance DNA and gas detection, are proposed through a simulation-based study. The proposed sensors are simulated by solving the Schrödinger equation using the mode space non-equilibrium Green's function formalism coupled self-consistently with a 2D Poisson equation under the ballistic limits. The dielectric and work function modulation techniques are used for the electrical detection of DNA and gas molecules, respectively. The behaviors of both the sensors have been investigated, and the impacts of variation in geometrical and electrical parameters on the sensitivity of sensors have also been studied. In comparison to other FET-based sensors, the proposed sensors provide not only higher sensitivity but also better electrical and scaling performances. The obtained results make the proposed DG-GNRFET-based sensors as promising candidates for ultra-sensitive, small-size, low-power and reliable CMOS-based DNA, and gas sensors.

In this paper, we propose a new Double Gate Junctionless (DGJ) MOSFET design based on both gate material engineering and drain/source extensions. Analytical models for the long channel device associated to the drain current, analog and radio-frequency (RF) performance parameters are developed incorporating the impact of dual-material gate engineering and two highly doped extension regions on the analog/RF performance of DGJ MOSFET. The transistor performance figures-of-merit (FoM), governing the analog/RF behavior, have also been analyzed. The analog/RF performance is compared between the proposed design and a conventional DGJ MOSFET of similar dimensions, where the proposed device shows excellent ability in improving the analog/RF performance and provides higher drain current and improved figures-of-merit as compared to the conventional DGJ MOSFET. The obtained results have been validated against the data obtained from TCAD software for a wide range of design parameters. Moreover, the developed analytical models are used as mono-objective function to optimize the device analog/RF performance using Genetic Algorithms (GAs). In comparison with the reported numerical data for Inversion-Mode (IM) DG MOSFET, our optimized performance metrics for JL device exhibit enhancement over the reported data for IM device at the same channel length.

In this paper, the analytical investigation of a new design including drain and source extensions is presented to assess the electrical behavior of cylindrical gate-all-around junctionless (GAAJ) MOSFET for high performance RF and analog applications. Analytical models for drain current and performance parameters are derived incorporating the effect of two highly doped extension regions. Various analog and RF parameters like transconductance, cut-off frequency, drain current drivability, voltage gain and linearity characteristics have also been investigated. The proposed design shows excellent ability in improving the analog performance and provides a good solution to enhance the RF behavior and linearity of GAAJ MOSFET for low cost and high performance analog/RF applications. The proposed model results have been validated against the data obtained from a commercially available numerical device simulator. Moreover, the developed analytical approaches are easy to be implemented into microelectronic software simulators and therefore allow the study of the GAAJ-based deep submicron circuits

The paper proposes a new reliable fault-tolerant scheduling algorithm for real-time embedded systems. The proposed scheduling algorithm takes into consideration only one bus fault in multi-bus heterogeneous architectures, caused by hardware faults and compensated by software redundancy solutions. The proposed algorithm is based on both active and passive backup copies, to minimize the scheduling length of data on buses. In the experiments, this paper evaluates the proposed methods in terms of data scheduling length for a set of DAG benchmarks. The experimental results show the effectiveness of our technique.

The paper proposes a new reliable fault-tolerant scheduling algorithm for real-time embedded systems. The proposed algorithm is based on static scheduling that allows to include the dependencies and the execution cost of tasks and data dependencies in its scheduling decisions. Our scheduling algorithm is dedicated to multi-bus heterogeneous architectures with multiple processors linked by several shared buses. This scheduling algorithm is considering only one bus fault caused by hardware faults and compensated by software redundancy solutions. The proposed algorithm is based on both active and passive backup copies to minimize the scheduling length of data on buses. In the experiments, the proposed methods are evaluated in terms of data scheduling length for a set of DSP benchmarks. The experimental results show the effectiveness of our technique.

This paper presents an intelligent control strategy that uses a feedforward artificial neural network in order to improve the performance of the MPPT (Maximum Power Point Tracker) MPPT photovoltaic (PV) power system based on a modified Cuk converter. The proposed neural network control (NNC) strategy is designed to produce regulated variable DC output voltage. The mathematical model of Cuk converter and artificial neural network algorithm is derived. Cuk converter has some advantages compared to other type of converters. However the nonlinearity characteristic of the Cuk converter due to the switching technique is difficult to be handled by conventional controller. To overcome this problem, a neural network controller with online learning back propagation algorithm is developed. The NNC designed tracked the converter voltage output and improve the dynamic performance regardless load disturbances and supply variations. The proposed controller effectiveness during dynamic transient response is then analyze and verified using MATLAB-Simulink. Simulation results confirm the excellent performance of the proposed NNC technique for the studied PV system. 

In this paper, a simulation study of the maximum power point tracking (MPPT) for a photovoltaic system using an artificial neural network is presented. Maximum power point tracking (MPPT) plays an important role in photovoltaic systems because it maximizes the power output from a PV solar system for all temperature and irradiation conditions, and therefore maximizes the power efficiency. Since the maximum power point (MPP) varies, based on the PV irradiation and temperature, appropriate algorithms must be utilized to track it in order maintain the optimal operation of the system. The software Matlab/Simulink is used to develop the model of PV solar system MPPT controller. The system simulation is elaborated by combining the models established of solar PV module and a DC/DC Boost converter. The system is studied using various irradiance shading conditions. Simulation results show that the photovoltaic simulation system tracks optimally the maximum power point even under severe disturbances conditions.

The back propagation (BP) algorithm has been very successful in training multilayer perceptron-based equalisers; despite its success BP convergence is still too slow. Within this paper we present a new approach to enhance the training efficiency of the multilayer perceptron-based equaliser (MLPE). Our approach consists on modifying the conventional back propagation algorithm, through creating an adaptive nonlinearity in the activation function. Experiment results evaluates the performance of the MLPE trained using the conventional BP and the improved back propagation with adaptive gain (IBPAG). Due to the adaptability of the activation function gain the nonlinear capacity and flexibility of the MLP is enhanced significantly. Therefore, the convergence properties of the proposed algorithm are more improved compared to the BP. The proposed algorithm achieves the best performance in the entire simulation experiments.

Impact of nonlinear piezoelectric constants on surface acoustic wave propagation on a piezoelectric substrate is investigated in this work. Propagation of acoustic wave propagation under uniform stress is analyzed; the wave equation is obtained by incorporating the applied uniform stress in the equation of motion and taking account of the set of linear and nonlinear piezoelectric constants. A new method of separation between the different modes of propagation is proposed regarding the attenuation coefficients and not to the displacement vectors. Detail calculations and simulations have made for Lithium Niobate (LiNbO3); transformations between modes of propagation, under uniform stress, have been found. These results leads to conclusion that nonlinear terms affect the acoustic wave propagation and also we can make controllable acoustic devices.