Papers by Keyword: Si

Abstract: This work demonstrates a highly efficient photocathode for water splitting in neutral electrolyte. It is based on a combination of the back-field p⁺ doped Si junction, and the nanostructured NiFe layered double hydroxide as co-catalyst. This extraordinary photoelectrochemical performance is primarily attributed to the catalyst-induced dramatic increase in active surface sites, and the suppression of hole recombination. Following the deposition of Pt nanoparticles between the Si junction and NiFe layered double hydroxide, the platinized photocathode (n⁺pp⁺ Si/Pt/NiFe LDH) exhibited an excellent photocurrent density of -4.98 mA/cm² at 0 V versus the standard reference (RHE) in 0.5 M Na₂SO₄ electrolyte. The superior quality of our cathode is demonstrated by the magnitude of the photoinduced current density (after dark current correction), which approaches the theoretical maximum. This achievement is attributed to the successful construction of built-in electric fields.

Abstract: In this work, the H3TRB performance of power modules with SiC MOSFET chips is investigated and compared to their silicon counterparts with similar electrical ratings. For this purpose, SiC MOSFETs and silicon IGBT chips are packaged in the same housing and with the same packaging technology and an H3TRB test is performed on both types of test devices. The results show that while both types exhibit an excellent H3TRB performance, the SiC MOSFETs had a significantly longer time to failure but also a wider failure distribution. Hence, the investigations presented in this paper confirm that properly designed SiC devices feature an equal or even better ruggedness against electro-chemical stress than standard silicon devics and are equally suitable for applications, which require operation in harsh environments.

Abstract: The 3 at% Al doped ZnO thin films were deposited on p-Si substrate with a native SiO₂ layer by spray pyrolysis method. Low temperature conduction behaviors were studied by analysis of impedance spectroscopy and low temperature ac conductivity. The results of impedance spectroscopy showed that the grain boundaries contributed to the resistivity of Al doped ZnO/SiO₂/p-Si heterojunction. The calculated activation energy was 0.073 eV for grain boundaries. The equivalent circuit to demonstrate the electrical properties of Al doped ZnO/SiO₂/p-Si heterojunction was a series connection of two parallel combination circuits of a resistor and a universal capacitor. Low temperature ac conductivity measurements indicated that the conductivity increased with temperature. Low temperature conductivity mechanism was electron conductivity, and the activation energy was 0.086 eV.

Abstract: In this manuscript, the structural properties such as the distance inter-reticular of samples is studied, In the fact, four samples were used symbolized as follows: E tAg(Å), the only difference is the thickness of the Silver buffer layer (tAg= 0, 50, 100 and 150 Å) to find out how the thickness of this layer depends on the structural characteristics of the Iron thin layer, all samples are deposited using molecular beam epitaxy (MBE) at room temperature onto Si (100) substrate. The structural properties of all samples examined using X-ray diffraction method at small and high angles. The small angles X-Ray diffraction curves confirmed to us that there is a clear difference between the surface structure of the samples by varying the number of Kiessig Fringes, Also high angles X-Ray diffraction curves assured us this difference through the clear variation in the angular positions of the peaks of Bragg and the distances inter-reticular values from a sample to the other.

Abstract: Magnesium alloys have the characteristic with high specific strength and lightweight property, it is widely used for auto mobile industry. Heat-resistant magnesium alloy is focused as a suitable material for weight reduction of the engine and power train parts in automotive field. In this study, microstructure and heat-resistant property in Mg-3mass%Al-1mass%Si (Mg-3%Al-1%Si) alloy with containing large amount of Sn (tin) were investigated. The alloys produced by permanent mold casting were investigated by optical microscope (OM), scanning electron microscopy (SEM) and measuring of bolt load retention at 423K. The heat-resistant property of Mg-3mass % Al-1mass % Si alloy with containing 6-13masss%Sn was higher compared with Sn free alloy and conventional Magnesium alloys (e.g. AZ91 and AM60 alloys).

Abstract: Powders consisting of Si-based nanostructures were synthesized by the extraction of Ca atoms from CaSi₂ powders using an inositol hexakisphosphate (IP6) aqueous solution. The raw CaSi₂ powders were simply immersed in a diluted IP6 solution, then dried. It is noted that the Si-based nanostructures were easily exfoliated from the powders to expose the surfaces corresponding to the Si {111} planes of the nanostructures. In addition, the Si-based nanostructures were also synthesized by metal atom extraction from SrSi₂, BaSi₂ and Mg₂Si using the IP6 aqueous solution. It was found that the nanostructures mainly including the amorphous Si-oxide phase were obtained for the IP6-treated SrSi₂, BaSi₂ and Mg₂Si powders. Moreover, the amorphous Si oxide-based nanostructures were synthesized from CaSi₂ using citric acid, malic acid, FeCl₃ and FeCl₂ aqueous solutions. It was demonstrated that the morphological and structural properties of the synthesized Si-based nanostructures depend on the silicide templates and the solutions.

Abstract: New approaches to enhance properties of silicon based quantum dot heterostructures for optical device application were developed. That is strain driven heteroepitaxy, small-sized quantum dots, elemental compositions of the heterointerface, virtual substrate, plasmonic effects, and the quantum dot charging occupation with holes in epitaxially grown Ge quantum dots (QDs) on Si (100). Experiments have shown extraordinary optical properties of Ge/Si QDs heterostructures and mid-infrared quantum dot photodetectors performance.

Abstract: Gate All-Around (GAA) is considered a key design feature for future CMOS technology. SiGe vs. Si selective etch is required for Si nanowire formation in GAA. It is confirmed the selective SiGe removal with commodity chemical (mixtures of hydrofluoric acid (HF), hydrogen peroxide (H2O2) and acetic acid (CH3COOH, HAc)), however the thick oxidized layer on Si NW was observed after commodity chemical process, which is indicated the significant Si NW loss. On the other hand, the formulated mixture ACT® SG-101, which is focusing on SiGe oxidizer, chemical pH, solvent polarity & corrosion inhibitor for chemical concept, was performed higher selectivity and lower Si loss than commodity chemical. The formulated mixture has also been used to form an inner spacer for cavity etch scheme and confirmed uniform cavity etch and inner spacer filling on topological test structure.

Abstract: Plasma etching, SEM and quantitative metallographic analysis technology were used to study the influence of Si on nucleation and growth process of spherical graphite in Ni-C alloys solidification microstructure. Pure Si, Ni-Si alloys and Fe-Si alloys were added into Ni-C melts respectively, and the solid microstructures were compared. The density, diameter size and roundness of spherical graphite were studied in this work to reveal the influence of Si on the morphology of graphite. The Ni-C alloy was etched by plasma etch, and the morphologies and composition of graphite nucleus were observed by scanning electron microscope (SEM) and electron energy spectrum analysis (EDS). The results suggested that the high Si melt zone in melt strongly promoted the enrichment and carbide of graphite, which both promoted the nucleation and growth of graphite. The change in Si content had a large effect on the roundness of the graphite, the higher the Si content, the better the roundness of the graphite.

Abstract: Si particles reinforced Al matrix composites (Sip/Al) have been widely used in the electronic packaging filed, and the higher mechanical and themo-physical properties are required for their application. In the present work, the effect of Si content (from 0.28 to 6.95 wt. %) in the matrix alloy on the microstructure, mechanical and thermo-physical properties of Sip/Al-Si-Mg composites have been investigated. Sip/Al-Si-Mg composites with 55 vol. % Si particles were prepared by pressure infiltration method. It has been found that the increment of Si content led to the improvement of relative density of composites. Moreover, the bending strength and thermal conductivity of Sip/Al-Si-Mg composites reached its maximum at Si content of 1.98 wt.%, which were 238.8MPa and 159.5W/(m∙K), respectively. Furthermore, the coefficient of thermal expansion (CTE) of Sip/Al-Si-Mg composites decreased with the increase of Si content. The mechanism of Si content on the microstructure of performance of Sip/Al-Si-Mg composites has been discussed.