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This study presents the development of a highly robust, pressureless, and void-free silver sinter-bonding technology for power semiconductor packaging. A bimodal silver paste containing silver nanoparticles and sub-micron particles was used, with polymethyl methacrylate (PMMA) as an additive to provide additional thermal energy during sintering. This enabled rapid sintering and the formation of a dense, void-free bonding joint. The effects of sintering temperature and PMMA content on shear strength and microstructure were systematically investigated. The results showed that the shear strength increased with rising sintering temperatures, achieving a maximum of 41 MPa at 300 °C, with minimal void formation due to enhanced particle necking facilitated by PMMA combustion. However, at 350 °C, the shear strength decreased to 35 MPa due to cracks and voids at the copper substrate-copper oxide interface caused by thermal expansion mismatch. The optimal PMMA content was found to be 5 wt.%, balancing sufficient thermal energy and void reduction. This pressureless sintering technology demonstrates significant potential for high-reliability applications in power semiconductor modules operating under high-temperature and high-stress conditions.
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http://dx.doi.org/10.3390/ma17215142 | DOI Listing |
Sci Adv
September 2025
James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK.
Narrow-linewidth lasers are essential for coherent optical applications, including communications, metrology, and sensing. Although compact semiconductor lasers with narrow linewidths have been demonstrated, achieving high spectral purity generally necessitates passive external cavities based on photonic integrated circuits. This study presents a theoretical and experimental demonstration of a monolithic optical injection locking topological interface state extended (MOIL-TISE) laser.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
Materials Genome Institute, School of Materials and Energy, Yunnan University, Kunming 650091, P. R. China.
Magnetic two-dimensional van der Waals (vdWs) materials hold potential applications in low-power and high-speed spintronic devices due to their degrees of freedom such as valley and spin. In this Letter, we propose a mechanism that uses stacking engineering to control valley polarization (VP), ferroelectricity, layer polarization (LP), and magnetism in vdWs bilayers. Through first-principles calculations, we predict that the T-VSI monolayer is a magnetic semiconductor with a sizable VP.
View Article and Find Full Text PDFDalton Trans
September 2025
Department of Chemistry & Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA.
Two-dimensional van der Waals (2D-vdW) semiconducting ferroelectrics, such as CuInPSe (CIPSe) and CuInPS (CIPS), offer unique opportunities for lightweight, scalable, low-power nanoscale electronic devices. However, the limited pool of functional 2D-vdW ferroics highlights the need for clear design principles that can be used to guide experiments. Here, we use first-principles density functional theory (DFT) to study how isovalent atomistic substitution at In and P sites modifies structure, polarization, and electronic properties in CIPSe and CIPS.
View Article and Find Full Text PDFAdv Mater
September 2025
Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, Poznań, 61-614, Poland.
AlN is a core material widely used as a substrate and heat sink in various electronic and optoelectronic devices. Introducing luminescent properties into intrinsic AIN opens new opportunities for next-generation intelligent sensors, self-powered displays, and wearable electronics. In this study, the first evidence is presented of AlN crystals exhibiting satisfactory mechanoluminescence (ML), photoluminescence (PL), and afterglow performance, demonstrating their potential as novel multifunctional optical sensors.
View Article and Find Full Text PDFAdv Mater
September 2025
College of Integrated Circuits & Micro-Nano Electronics, Fudan University, Shanghai, 200433, China.
High-operating-temperature (HOT) mid-wavelength and long-wavelength infrared photodetectors have emerged as critical enablers for eliminating bulky cryogenic cooling systems, offering transfromative potential in developing compact, energy-efficient infrared technologies with reduced size, weight, power, and cost. Focusing on infrared photodiodes, this review first discusses the fundamental mechanisms limiting performance at elevated operating temperatures. Subsequently, the progress in conventional epitaxial semiconductors, such as HgCdTe, InAsSb, and III-V type-II superlattice is reviewed, highlighting the evolution of device architectures designed to effectively suppress dark currents and approach background-limited performance.
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