Papers by Keyword: Semiconductor

Abstract: The next space missions require power levels that current space qualified semiconductor technology cannot provide. The silicon carbide devices are considered to overcome these challenges, and provide the required technical performance. European space industry is asked in individual meetings about their specific needs and requirements, this information is gathered, classified and presented to the silicon carbide manufacturers. This work is the connection between the two industries to better understand the requirements and applications, and build a new business case for the SiC devices in space applications.

Abstract: In this recent study, thin films of pure tin oxide (SnO₂) denoted by TO and tin oxide doped with nickel (Ni) and zinc (Zn) at varying concentrations of 5 wt.%, 10 wt.%, and 15 wt.% were developed and characterized on ordinary glass substrates. The deposition of the films was conducted using the sol-gel technique (Dip-coating). These films are referred to as (Ni-Zn) co-doped tin oxide (NZTO) films that can be used in diverse applications such as gas and UV sensors. The effect of Ni/Zn co-doping on the structural, morphological, optical, and electrical properties of undoped SnO₂ was investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-Vis) spectroscopy. The electrical properties were further examined using the quadruple method. XRD analysis revealed that all samples were polycrystalline with a rutile-type tetragonal crystal structure, predominantly oriented along the (110) plane, but changed to (100) and (200) orientations with high doping contents. The grain size values exhibited a decreasing tendency with increasing co-doping content. The SEM images indicated that the films possessed a porous surface and were made up of well-defined and homogenously dispersed spherical and polyhedron-shaped nanoparticles, which were influenced by doping with Ni and Zn. The FTIR study showed that all the films exhibit the Sn-O-Sn, Sn-O, Sn-OH, and H-O vibration peaks. The NZTO films enhanced the crystal structure and raised the optical energy gap from 4.03 eV for TO to 4.09 eV for NZTO. The thickness also increased from d = 353.44 nm for pure TO films to d = 448.43 nm for films doped with 15% NZTO. The highest transmittance value was observed to be 93% for TO within the visible range. Hall effect measurements indicated that TO exhibited n-type conductivity and p-type conductivity when doped with 5%, 10%, or 15% NZTO. This allows photodetectors based on TO to show great sensitivity to UV light.

Abstract: Due to their ability to combine the physical separation of membrane filtration with organic degradation in one unit, photocatalytic membranes have demonstrated enormous potential for application in energy-efficient water purification and wastewater treatment. Titanium dioxide (TiO₂) is the substance most frequently utilized to create photocatalytic membranes. However, TiO₂'s use is constrained by its substantial band gap (3.2 eV). On the other hand, tungsten trioxide (WO₃) has a fairly small band gap (2.7-2.8 eV) which makes it able to absorb visible light, making the photocatalytic process more efficient. This article examines recent developments in WO₃ photocatalytic membranes for wastewater treatment and water purification with a focus on the photocatalytic mechanism, photocatalytic membrane fabrication and development. The mechanism of WO₃ semiconductor in pollutant removal is explained in detail. Blending, coating and grafting methods, which are three methods commonly used when fabricating photocatalytic membranes, are discussed. Likewise with the development of WO₃ photocatalytic membranes using pure WO₃, heterojunction or doping with metal.

Abstract: This paper presents a numerical simulation of a dual-junction tandem GaInp/GaAs cell made from top GaInp and bottom GaAs cells. For this purpose, we utilized a numerical simulation tool. Two methodologies were proposed, the first method consists of simulating each base layer cell of the top and bottom separately, and the second method simulated both layers in one file, to simulate both in one file. For improved electric characteristics of tandem solar cells, the current-match requirement between the top and bottom cells should be satisfied, necessitating the careful design of parameters. The top base GaInp layer thickness is adjusted to match this requirement. The solar spectrum reaching the lower cell is analytically calculated by subtracting the top cell spectrum from the total spectrum. the optimal value of short current density corresponds with a top cell base thickness of 0.8 µm, this results in an open circuit voltage of 2.45 V, a short circuit current of 15.7 Am/cm², a fill factor of 91 %, an efficiency of 35 % for the first method and the second method used a script file designed to verify the above results and confirmed the values to be; 2.68 V open circuit voltage, 15.26 Am/cm², a short circuit current, 90 % fill factor, and 36.86 % efficiency under AM 1.5 G solar spectrum.

Abstract: The aim of this study is discussing the results achieved on undoped and Ni-doped bulk LaCoO₃ samples synthesized by solid-state reaction. The crystal structures of the samples were analyzed by x – ray diffraction (XRD) and Rietveld refinement of the XRD patterns was used to test the quality of the samples, the results of this procedure confirmed a single phase of LaCo_1-xNi_xO₃ for (x=0 and 0.05) with rhombohedral crystal structure (space group :). The main interest in this class of materials is the possibility of improving the values of Seebeck coefficient and electrical resistivity through chemical doping. The Seebeck coefficient and electrical resistivity were investigated from room temperature (RT) to 450 K, near RT the LaCoO₃ system showed a large negative Seebeck coefficient, but it changed to positive value with increasing temperature while the LaCo_0.95Ni_0.05O₃ composition showed a positive Seebeck coefficient throughout all the temperature range. Hence, within this study the Ni substitution led to decrease the electrical resistivity of the samples to one order of magnitude as a result of the partial substitution of Co³⁺ in LaCoO₃ by Ni²⁺. LaCoO₃ was chosen for this thermoelectric test because cobalt oxides have extensive applications.

Abstract: Perovskite semiconductor have gained increasing attention in the recent years. However, pristine halide perovskites often faces bottle-neck related to low their stability. Herein, for the first time synthesis and fabrication of CsPbBr3/PAN fiber composite with electrospinning method is reported. CsPbBr3 quantum dots (QDs) embedded PAN fiber were successfully fabricated based on the XRD and FTIR test result. The result demonstrates electrospun fiber stable for over than one week in the condition of being immersed in water. The CsPbBr3 QDs was synthesized by Ligand Assisted Reprecipitation Process (LARP) method. The average particle size of our CsPbBr3 particle sizes ranging from 80 to 240 nm. Our findings reveal that the effect of variations between toluene and acetone had an effect on the size of the fiber and the intensity of photoluminescence reduction of the CsPbBr3/PAN fiber composite. Which is the smallest fiber and the lowest reduction intensity belongs to the 4:1 variation, namely with a fiber size of a 727.56 nm and a percentage decrease in intensity of 66,67%.

Abstract: Multilayer antireflection coatings have been modeled in visible and infrared regions (1-5 μm) bands to increase the transmittance of glass and silicon substrates. The transmittance was studied using different semiconductor materials with different thickness ( single, double and three) layers to determine the best design that depends on the manufacture of antireflection coatings at low costs and few layers of coatings to reduce the stress generated by the increased number of layers. MgF₂ and TiO₂ materials are used in the visible region (300-1000 nm) at the central wavelength (500 nm). The transmittance of MgF₂ single–layer with a quarter waves optical thickness is reached (98.61%) and the transmittance value is (98.74%) for arrangement (. The transmittance of the infrared spectrum for antireflection coating materials depends on the thickness and temperature of these materials because of scattering and absorption in such materials. LaF₃, ZrO₂, ZnSe, and CdTe materials are used in the infrared region at a design wavelength (3000 nm). The maximum value of transmittance is around (99.99%) for the best design that consisting of three layers with quarter wavelength thickness. Keywords: Antireflection Coatings, Multilayers, Semiconductor, Transmittance

Abstract: P-BiOBr/CoFe₂O₄ nanocomposite was fabricated through a surfactant-free hydrothermal route and combined with electron acceptors (IO₄^- and S₂O₈^2-) for the first time to examine the palm oil mill effluent (POME) degradation and concurrently evaluated the biogas formation under visible light irradiation. The POME degradation efficiency reached 100% in 120 min over P-BiOBr/CoFe₂O₄/IO₄^-, which was much higher than the P-BiOBr/CoFe₂O₄/S₂O₈^2- (80.6%). Interestingly, the evaluation of the biogas production demonstrated that the P-BiOBr/CoFe₂O₄/IO₄^- photocatalysis generated greater amount of biogas (CH₄ + CO₂) compared to other systems. The great photocatalytic enhancement was due to the efficient charge carrier separation thanks to the Z-scheme heterojunction between P-BiOBr and CoFe₂O₄, and the electron trapping by IO₄^-. The hydroxyl radicals and photogenerated holes contributed majorly to POME degradation. Ultimately, the P-BiOBr/CoFe₂O₄ with IO₄^- and S₂O₈^2- assisting under visible light provided an effective and feasible method to degrade POME.

Abstract: In this study, the photovoltaic properties of zinc oxides are investigated. Different stoichiometries of zinc oxide can be made using vacuum deposition. Thermally evaporated zinc produces thin films of ZnO composed of orthorhombic and tetragonal phases that define the material's characteristics and performance. On-thermal plasma has removed a very thin layer from the surface of the thin film, known as non-thermal plasma, and made a surface cleanup. Measurements of the Atomic Force Microscope (AFM) show that the value of the granular volume rate increases when the duration of exposure to non-heat plasma increases. Measurements of the Atomic Force Microscope (AFM) show that there is an increase in thin film surface roughness values (Roughness, Sq), as well as the square root of the average roughness of the thin film surface (RMS), and this increase in roughness appears as the duration of exposure to non-thermal plasma increases.

Abstract: This work aims to prepare BiOI films via simple heating of BiI₃ materials and study their characters from structural, optical, and morphology perspectives. In the heating process, we varied the heating treatment time. In addition, the solar cell performance of prepared BiOI films was tested. In BiOI preparation, we deposited BiI₃ films first onto FTO substrates via BiI₃ heating in the air using a closed chamber at the temperature of 360 °C for 30, 45, and 120 minutes. The deposited BiI₃ films were then rinsed with water/ethanol and re-heated at 350 °C for 30 minutes. As a result, by increasing the heating treatment time, it could form thicker BiOI films. All the resulting films confirmed the BiOI characters. A longer BiI₃ heating time could direct the growth of BiOI crystal, wavelength red-shift, and flake structure. In the electrochemical solar cell study, it was known that BiOI films had a lower performance compared to the reported results. After a certain thickness (~1.3 μm), the device's open-circuit voltage and current decreased.