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ß-Ga2O3/4H-SiC heterojunction diodes were fabricated by depositing β-Ga2O3 thin films on 4H-SiC substrates using radio frequency sputtering. X-ray diffraction (XRD) analysis revealed increased reflectivity of β-Ga2O3 ( 4 ¯ 02), ( 2 ¯ 02) and ( 6 ¯ 03) crystal planes with optimized sputtering power. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were performed to confirm grain size and distribution. The Hall mobility (30.16 cm2/V ∙ s) and carrier concentration (3.14 × 1014 cm–3) showed with large and homogeneous grain distribution thin films. For these thin films, mobility and carrier concentration value could improve up to 9% and 55%. The effect of these electrical characteristics was ascribed to reduction of the grain boundary scattering. The I–V characteristics along with Hall measurement of the heterojunction diode suggest that the improvement in the threshold voltage and current density is caused by a substantial enhancement in charge carrier mobility. [ABSTRACT FROM AUTHOR]

MoSi2-based composites are promising structural materials for high-temperature applications. MoxW1−xSi2 (x = 1, 0.9, 0.8, and 0.7) powders were successfully synthesized by self-propagating high-temperature synthesis. These powders were used to fabricate heating elements, which were then subjected to a post-annealing process to improve the structural quality. To determine the influence of the W content (0–30 mol%) on the characteristics of MoxW1−xSi2 composites, the surface morphologies, densities, and bending strengths of the MoxW1−xSi2 heating elements were investigated. Moreover, to validate the durability of the MoxW1−xSi2 heating elements, an accelerated degradation test (ADT) was conducted at temperatures up to 1700°C (heating rate = 5°C/min). The MoxW1−xSi2 heating element with 30 mol% of W exhibited a high density, a high bending strength, and superior durability after the ADT test. In contrast, the MoxW1−xSi2 heating element with 0 mol% of W showed inferior durability owing to the formation of bubbles at the MoxW1−xSi2 /SiO2 interface. Thus, the addition of W enhances the reliability and durability of MoxW1−xSi2 composites as heating elements. [ABSTRACT FROM AUTHOR]

Abstract: Al2O3/Cu composite films, useful for film resistors, were successfully fabricated at room temperature via aerosol deposition (AD). Microstructures of the Al2O3/Cu composite films were analyzed to understand the correlations between the surface morphologies and Al2O3/Cu ratio. A scratch test was carried out by gradually increasing the load applied to the Al2O3/Cu composite films. We also evaluated the adhesion ability by measuring the tensile strength between Al2O3/Cu composite films and Al2O3 substrate. The results confirmed that the adhesive properties of Al2O3/Cu composite films were strongly influenced by two adhesive mechanisms: mechanical interlocking and anchoring bonds between the films and Al2O3 substrate. When a powder mixture containing 50 wt% of Al2O3 and Cu was deposited on the substrate, high mechanical properties and suitable resistivity were simultaneously achieved at approximately 8.02 MPa and 85.2 mΩ cm, respectively due to effective mechanical interlocking and anchoring bonds. The results further suggest that room-temperature AD method is highly favorable to fabricate heterogeneous composite films for application to film resistors.Graphical Abstract: [ABSTRACT FROM AUTHOR]