: In the present work, thin films of Cr/NiO/Ni are deposited on glass substrates using RF magnetron sputtering technique. The uniformity and homogeneity of the prepared films were controlled by varying the power of the source, the targetsubstrate distance and the pressure of the plasma gas which is argon. In order to test the Preisach Model, we carried out measurements according to two directions: parallel and perpendicular to the substrate plane using a Vibrating Sample Magnetometer at room temperature. Good agreement has been obtained by comparing the experimental hysteresis loops to the ones determined using Preisach model. We conclude that this model is powerful in predicting the magnetic properties of multilayer systems.

In the last few years, an accelerated trend toward the miniaturization of nanoscale circuits has been recorded. In fact, this has been reflected by numerous enhancements at different levels of multi‐gate structures such as the channel body or the gate material. Our aim in this work is to investigate the reliability performance of junctionless DG MOSFET including graded channel aspect. The behavior of the considered device is analyzed numerically using ATLAS‐2D simulator, where degradation phenomena are accounted for in the model. The variation of some analog/RF criteria namely the transconductance and cut‐off frequency are established in terms of the channel length and traps density. The obtained responses indicate the superior immunity of the graded channel device against traps‐induced degradation in comparison to the conventional structure. Thus, this work can offer more insights regarding the benefit of adopting the channel doping engineering for future nanoscale electronic applications.

In this paper, a new particle swarm optimization‐based approach is proposed for the geometrical optimization of the nanowires solar cells to achieve improved optical performance. The proposed hybrid approach combines the 3‐D numerical analysis using accurate solutions of Maxwell's equations and metaheuristic investigation to boost the solar cell total absorbance efficiency. Our purpose resides on modulating the electric field and increasing the light trapping capability by optimizing the radial solar cell geometrical parameters. Moreover, a comprehensive study of vertical core‐shell nanowire arrays optical parameters such as the integral absorption, reflection, and total absorbance efficiency is carried out, in order to reveal the optimized radial solar cells optical performance for low‐cost photovoltaic applications. We find that the proposed hybrid approach plays a crucial role in improving the nanowires solar cells optical performance, where the optimized design exhibits superior total absorbance efficiency and lower total reflection in comparison with those provided by the conventional planar design. The obtained results make the proposed global optimization approach valuable for providing high‐efficiency nanowires solar cells.

Bilayer of nickel and nickel oxide were deposited on glass substrates using RF magnetron sputtering technique. The magnetic properties of the prepared thin films were carried out at room temperature in both parallel and perpendicular magnetic field to the sample. The Preisach model was applied to provide a mathematical model of the magnetic hysteresis loop in the case of parallel geometry, along the easy axis of the bi-layer NiO / Ni. Good agreement was obtained between the theoretical and experimental results.

Tin oxide SnO₂ thin films were deposited by sol gel method on glass substrates. The as-deposited thin films were then annealed at 550 °C for different time durations (15, 30, 60 and 120 min). Structural and morphological investigations were carried out on all samples by X-ray diffraction method and atomic force microscopy while optical properties were obtained with UV–Visible spectrophotometer. XRD patterns reveals that the samples possess polycrystalline with rutile structure of SnO₂ without any secondary phase. AFM image showed that SnO₂ thin films having a smooth surface morphology. The optical properties in the visible range showed that the deposited layers have a high transmission factor. The optical band gap energy varies in the range of 3.61–3.73 eV. Finally, ultraviolet (UV) detection properties of samples as an active layer in UV photodetector devices were investigated. Current-voltage characteristics of the SnO₂ thin films are performed under dark and light environment, which show low dark current of 22.9 nA with a linear behavior and high current ration > 10⁴ under 2 V applied voltage and 120 min as annealing time. Whereas, high photocurrent is observed for samples annealing for 30 min. Moreover, the transient photoresponse of the fabricated device is reported under different annealing times.

In this paper, a new design methodology by optimizing the silicon/organic interface morphology is proposed to achieve superior optical behavior for pentacene-based organic/inorganic solar cells. Our purpose dwells on reducing the refracting light in the silicon and improves the absorbance behavior in the solar cell. In this context, a numerical model based on accurate solutions of Maxwell’s equations is developed in order to study the impact of both interface texturization morphologies (triangular and grooves) on the optical absorbance and electrical performance. It is found that the proposed design morphology has profound implication on modulating the electric field, which increases the light trapping capability. It is also confirmed that the overall electrical performance is significantly improved as compared to the conventional organic/inorganic solar cells, where the proposed design exhibits superior integral absorption behavior and large interface area. Moreover, a new hybrid approach by combining of the numerical and metaheuristic models is developed to boost the device performance by optimizing the interface morphology. The obtained results make the proposed design methodology valuable for providing high-efficiency organic/inorganic solar cells.

In this paper, graded channel doping (GCD) and junctionless paradigms are proposed as a new ways to improve the optical controlled field effect transistor (OCFET) and bridging the gap between the high responsivity and ultra-low power consumption. A careful mechanism study based on numerical investigation and a performance comparison between the proposed structure and both the conventional inversion mode (IM-OCFET) and the junctionless (JL-OCFET) designs is presented. It is found that the graded channel doping feature can efficiently improve the overall device optical and electrical performances. Moreover, the proposed design exhibits superior device figures of merit (FoMs) and provides ultra-sensitivity behavior as compared to both the conventional IM-OCFET and the JL-OCFET counterparts. Our investigation reveals also the outstanding capability of the proposed structure for offering the weak signal detection advantage that demonstrates the unique property of our phototransistor with GCD aspect. These characteristics not only underline the excellent switching behavior of the proposed design but also demonstrate the ability for overcoming the trade-off between the low cost and readily fabrication process in addition to ultrasensitive aspect with low power consumption. This makes the proposed GCD-JL-OCFET a potential alternative for developing low power communication systems.

In this paper, a new junctionless optical controlled field effect transistor (JL-OCFET) and its comprehensive theoretical model is proposed to achieve high optical performance and low cost fabrication process. Exhaustive study of the device characteristics and comparison between the proposed junctionless design and the conventional inversion mode structure (IM-OCFET) for similar dimensions are performed. Our investigation reveals that the proposed design exhibits an outstanding capability to be an alternative to the IM-OCFET due to the high performance and the weak signal detection benefit offered by this design. Moreover, the developed analytical expressions are exploited to formulate the objective functions to optimize the device performance using Genetic Algorithms (GAs) approach. The optimized JL-OCFET not only demonstrates good performance in terms of derived drain current and responsivity, but also exhibits superior signal to noise ratio, low power consumption, high-sensitivity, high I_ON/I_OFF ratio and high-detectivity as compared to the conventional IM-OCFET counterpart. These characteristics make the optimized JL-OCFET potentially suitable for developing low cost and ultrasensitive photodetectors for high-performance and low cost inter-chips data communication applications.

In this paper, a new metallic thin film engineering aspect is proposed to achieve superior absorption for TiO₂/Metal/TiO₂ on Silicon substrate UV-based photodetectors (PDs). The overall device optical performance comparison with three dissimilar metallic layers (Au, Ti, and Ag) is performed numerically using accurate solutions of Maxwell׳s equations. A comprehensive study of the device optical parameters such as the integral absorption, reflection, and rejection ratio is carried out, in order to reveal the device optical performance for UV optical interconnects and environment monitoring applications. We find that the optical performance are considerably improved as compared to the conventional design, where the proposed design offers superior integral absorption and lower total reflection with an acceptable rejection ratio in comparison with those provided by the conventional one. These improvements suggest the opportunity for optimizing the proposed design using particle swarm optimization (PSO) approach for achieving higher optical performance, where excellent capability is recorded in enhancing the device optical behavior. The obtained results make the prop sed device very efficient for compatible CMOS modern technology.

In this paper, new multilayer design based on ZnO/Ag/ZnO structure is proposed as a new way to achieve UV-based photodetector (PD) with superior optical behavior. Our purpose resides on reducing the refracting light and achieving an effective absorption in the Ag metallic sub-layers. New numerical model based on accurate solutions of Maxwell’s equations is developed in order to elucidate the impact of the metallic sub-layers on the UV-PD optical performance. An overall analysis regarding the optical parameters such as the integral absorption and the total reflection is conducted. It is found that the metallic sub-layers have profound implications on modulating the electric field in the structure and facilitating photon forward scattering in the ZnO sub-layers which led to better optical behavior. Moreover, Particle Swarm Optimization (PSO) approach is proposed as a metaheuristic technique to reach effectiveness absorption through carefully adjusting the Ag and ZnO sub-layers thickness. It is confirmed that the optimized design can provide superior optical performance as compared to the conventional counterpart, where the optimized multilayer design exhibits an enhancement of 60% in the integral absorption over ZnO-based PD. The obtained results make the proposed multilayer design efficient for providing high performance PDs for communication applications.

In this paper, a new hybrid approach by combining numerical investigation and Support Vector Machines (SVMs) classifier is proposed to study the thermoelectric performance of nanoscale Double Gate Junctionless DG JL MOSFET. In this context, a new Figure of Merit (FoM) parameter which combines both electrical and reliability characteristics is proposed. Moreover, the impact of Gaussian channel doping profile (GCD) in enhancing the DG JL MOSFET reliability against the self-heating effects (SHEs) is presented. The proposed design thermal stability and electrical characteristics are investigated and compared with those of the conventional structure in order to reveal the device performance including SHEs. It is found that the amended channel doping has a profound implication in improving both the device electrical performance and the reliability against the undesired self-heating and short channel effects (SCEs). Furthermore, the transistor thermal behavior analysis involves classification of the device performance by taking into account the device reliability. For this purpose, SVMs are adopted for supervised classification in order to identify the most favorable design configurations associated with suppressed SHEs and improved electrical performance. We find that the proposed design methodology has succeeded in selecting the better designs that offer superior reliability against the SHEs. The obtained results suggest the possibility for bridging the gap between high electrical performances with better immunity to the SHEs.

In this paper, a new MSM-UV-photodetector (PD) based on dual wide band-gap material (DM) engineering aspect is proposed to achieve high-performance self-powered device. Comprehensive analytical models for the proposed sensor photocurrent and the device properties are developed incorporating the impact of DM aspect on the device photoelectrical behavior. The obtained results are validated with the numerical data using commercial TCAD software. Our investigation demonstrates that the adopted design amendment modulates the electric field in the device, which provides the possibility to drive appropriate photo-generated carriers without an external applied voltage. This phenomenon suggests achieving the dual role of effective carriers’ separation and an efficient reduce of the dark current. Moreover, a new hybrid approach based on analytical modeling and Particle Swarm Optimization (PSO) is proposed to achieve improved photoelectric behavior at zero bias that can ensure favorable self-powered MSM-based UV-PD. It is found that the proposed design methodology has succeeded in identifying the optimized design that offers a self-powered device with high-responsivity (98 mA/W) and superior I_ON/I_OFF ratio (480 dB). These results make the optimized MSM-UV-DM-PD suitable for providing low cost self-powered devices for high-performance optical communication and monitoring applications.

In this paper, an electromagnetic approach based on cavity model in conjunction with electromagnetic knowledge was developed. The cavity model combined with London’s equations and the Gorter-Casimir two-fluid model has been improved to investigate the resonant characteristics of high Tc superconducting circular microstrip patch in the case where the patch is printed on uniaxially anisotropic substrate materials.  Merits of our extended model include low computational cost and mathematical simplify. The numerical simulation of this modeling shows excellent agreement with experimental results available in the literature. Finally, numerical results for the dielectric anisotropic substrates effects on the operating frequencies for the case of superconducting circular patch are also presented.

In this paper, the effects of both anisotropies in the substrate and superstrate loading on the resonant frequency and bandwidth of high-Tc superconducting circular microstrip patch in a substrate-superstrate configuration are investigated. A rigorous analysis is performed using a dyadic Galerkin's method in the vector Hankel transform domain. Galerkin's procedure is employed in the spectral domain where the TM and TE modes of the cylindrical cavity with magnetic side walls are used in the expansion of the disk current. The effect of the superconductivity of the patch is taken into account using the concept of the complex resistive boundary condition. London's equations and the two-fluid model of Gorter and Casimir are used in the calculation of the complex surface impedance of the superconducting circular disc. The accuracy of the analysis is tested by comparing the computed results with previously published data for several anisotropic substrate-superstrate materials. Good agreement is found among all sets of results. The numerical results obtained show that important errors can be made in the computation of the resonant frequencies and bandwidths of the superconducting resonators when substrate dielectric anisotropy, and/or superstrate anisotropy are ignored. Other theoretical results obtained show that the superconducting circular microstrip patch on anisotropic substrate-superstrate with properly selected permittivity values along the optical and the non-optical axes combined with optimally chosen structural parameters is more advantageous than the one on isotropic substrate-superstrate by exhibiting wider bandwidth characteristic.

In this paper, an efficient full-wave analysis of a circular microstrip patch printed on suspended and composite substrates is performed using a dyadic Green’s function formulation. Galerkin’s technique is used in the resolution of the integral equation of the electric field. The TM set of modes issued, from the magnetic wall cavity model, are used to expand the unknown currents on the circular patch. The radiation patterns are expressed regarding the transforms of the currents. The convergence of the method is proven by calculating the resonant frequencies, half-power bandwidths, and quality factors for several configurations. The computed results are found to be in excellent agreement with those observed in the literature. The numerical results obtained show that the bandwidth increases with the increase in the thickness of the suspended or composite substrates, especially for low permittivity of the second layer. Also, it is demonstrated that the resonant frequencies of the circular microstrip patch on suspended and composite substrates can be adjusted to obtain the maximum operating frequency of the antenna. Finally, the effect of the presence of the second layer under the circular patch on the radiation patterns is also investigated.

In this paper, a new particle swarm optimization‐based approach is proposed for the geometrical optimization of the nanowires solar cells to achieve improved optical performance. The proposed hybrid approach combines the 3‐D numerical analysis using accurate solutions of Maxwell's equations and metaheuristic investigation to boost the solar cell total absorbance efficiency. Our purpose resides on modulating the electric field and increasing the light trapping capability by optimizing the radial solar cell geometrical parameters. Moreover, a comprehensive study of vertical core‐shell nanowire arrays optical parameters such as the integral absorption, reflection, and total absorbance efficiency is carried out, in order to reveal the optimized radial solar cells optical performance for low‐cost photovoltaic applications. We find that the proposed hybrid approach plays a crucial role in improving the nanowires solar cells optical performance, where the optimized design exhibits superior total absorbance efficiency and lower total reflection in comparison with those provided by the conventional planar design. The obtained results make the proposed global optimization approach valuable for providing high‐efficiency nanowires solar cells.

The performances of two full differential operational amplifiers (Op-Amps) telescopic and folded-cascode are evaluated to satisfy the stringent requirements on the amplifier to be used in a Multiplying Digital-to-Analog Converter (MDAC) stage of a pipelined ADC (Analog-to-Digital Converter). The paper shows the solutions found to reach high gain, wide bandwidth and short settling time without degrading too much the output swing. The Op-Amp specifications are extracted according to the ADC requirements, then the two Op-Amp topologies are designed, tested and their performances are compared. Simulation results show that the Op-Amp folded-cascode topology is more suitable architecture for pipelined ADC than the telescopic one. Moreover, the use of this type of Op-Amp generates an Integral Non-Linearity (INL) error less than that of the telescopic one. The analyses and simulation results are obtained using 0.18 µm AMS (Austria Mikro System) CMOS process parameters with a power supply voltage of 1.8V. The predicted performance is verified by analysis and simulations using Cadence EDA simulator.