Iron thin films were deposited on glass substrates using RF magnetron sputtering and their optimal deposition conditions were determined. The structure properties were analyzed using x-ray diffraction (XRD) and their magnetic hysteresis loops were obtained by Vibrating Sample Magnetometer (VSM) at room temperature. In this situation, the magnetic field is either parallel or perpendicular to the substrate plane. The main contribution of this work is to characterize the thin layers and present a mathematical model that can get best fit of the characteristics B(H). By using Preisach model, good agreement was obtained between theoretical and experimental results in both cases.

Silicon oxide (SiO₂) is a good dielectric material in metal-oxide-semiconductor (MOS) structures. The improved SiO₂ quality requires adequate study of doping diffusion in this structure to maintain the absence of the different impurities in the interface Poylsilicon/SiO₂. For this we studied a theoretical model of boron diffusion before and after thermal annealing in a highly-doped polysilicon films. The model takes into account the distribution of vacancy mechanism by associating parameters and effects related to high concentrations. Based on the literature the model is solved using the engineering software tool MATLAB, following a well-defined algorithm. The model is validated with the help of simulation results obtained from Silvaco.

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 photoluminescence, structural and morphological 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 pores. Besides that a sharp Raman peak at 298 cm-1 is observed which reflects Raman active transverse optical mode of the introduced Ge which indicates 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

In this paper, a new junctionless optical controlled field effect transistor (JL-OCFET) is proposed to improve the device performance as well as achieving low power consumption. An overall optical and electrical performances comparison of the proposed junctionless design and the conventional inversion mode structure (IM-OCFET) has been developed numerically, to assess the optical modulation behavior of the OCFET for low power optical interconnections applications. It is found that, the proposed design demonstrates excellent capability in decreasing the phototransistor power consumption for inter-chip optical communication application. Moreover, the proposed device offers superior sensitivity and ION/IOFF ratio, in addition to lower signal to noise ratio as compared to the conventional IM-OCFET structure. The obtained results indicate the crucial role of the junctionless (JL) design in enhancing the phototransistor performance and reducing the total power dissipation. Such a very sensitive OCFET can be very promising in the future low power optical receiver less compatible to CMOS modern technology for high-quality interchips data communication applications.

The use of uniformly doped channel, source and drain regions presents the well-known problem of the high series resistance associated to the extensions, which degrades the electrical performance of the nanoscale multi-gate junctionless MOSFETs. Therefore, new designs and accurate investigation of nanoscale double gate junctionless (DGJ) MOSFET including the defects at the interface Si/SiO2 are required for the comprehension of the fundamentals of such device behavior against the ageing phenomenon. Based on 2D numerical investigation of a nanoscale DGJ MOSFET, in the present work a numerical study for I-V and small signal characteristics, by including both the highly doped extension regions and the interfacial defects, is presented. The investigated design, which is a technologically feasible technique by introducing only one ion implantation step, provides a good solution to improve the device immunity against the interfacial defects under critical conditions, where the channel length is taken equals to 10 nm. In this context, I-V, analog and linearity characteristics are investigated by an appropriate 2-D numerical modeling, where the obtained results are compared with those of the conventional DGJ MOSFETs. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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.