This paper describes the characterization of SAW propagation in layered substrate and overlayered structures. The software based on the finite element method and spectral domain analysis was newly developed and applied to the characterization of SAW propagation under an infinitely-long Al interdigital transducer on a rotated Y-cut LiTaO(3)/sapphire substrate. Because of the finite LiTaO(3) thickness, a series of spurious resonances appears. It is shown that the excitation strength of the spurious resonances changes with frequency as well as the rotation angle, which reflects the frequency and rotation angle dependence of the energy leakage. Next, the analysis was carried out for SAWs propagating in a SiO(2) layer/Al IDT/42 degrees YX-LiTaO(3) structure. It is shown that the influence of the SiO(2) layer is significantly dependent on the location where the SiO(2) layer is deposited. In particular, it is shown that when the SiO(2) layer is deposited only on top of the electrodes, the SAW reflectivity increases compared with when the SiO(2) layer is deposited between and on top of electrodes.
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http://dx.doi.org/10.1109/TUFFC.2009.1343 | DOI Listing |
Opt Express
January 2025
The perceived colors of silicon-on-insulator (SOI) wafers with etched Si surface layers of thickness 90 nm to 30 nm vary from turquoise to purple to golden. Measured reflectance curves spanning ultraviolet, visible, and near infrared wavelengths have an amplitude modulated oscillatory pattern. Multilayer reflectance calculations indicate the oscillatory pattern results from the 2 µm thick buried SiO layer which functions as a nearly lossless reflective Fabry-Perot etalon in the near infrared where SiO and Si are transparent.
View Article and Find Full Text PDFDiscov Nano
January 2025
Nuclear and Energy Research Institute, IPEN, CNEN/SP, Av. Prof. Lineu Prestes, 2242, São Paulo, SP, CEP05508-000, Brazil.
Gold nanoparticles are widely used in biomedical applications due to their unique properties. However, traditional synthesis methods generate contaminants that cause cytotoxicity and compromise the biocompatibility of the nanomaterials. Therefore, green synthesis methods are essential to produce pure and biocompatible nanoparticles, ensuring their effectiveness in biomedical applications.
View Article and Find Full Text PDFJ Mech Behav Biomed Mater
January 2025
School of Materials Science and Engineering, University of Jinan, Jinan, 250022, China. Electronic address:
Silicon nitride (Si₃N₄) ceramics exhibit excellent mechanical properties and biocompatibility, making them highly suitable for biomedical applications, particularly in implants. In this study, the mechanical properties and bioactivity of Si₃N₄ ceramics with varying amounts of Y₂O₃-Al₂O₃-SiO₂ sintering aids were investigated. Increasing the sintering additive content from 4 wt% to 8 wt% substantially improved the bulk density of the ceramics, leading to notable enhancements in mechanical properties.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Faculty of Arts and Sciences, Bolu Abant Izzet Baysal University, 14280 Bolu, Turkey.
We report on a procedure for extracting the SPICE model parameters of a RADFET sensor with a dielectric HfO/SiO double-layer. RADFETs, traditionally fabricated as PMOS transistors with SiO, are enhanced by incorporating high-k dielectric materials such as HfO to reduce oxide thickness in modern radiation sensors. The fabrication steps of the sensor are outlined, and model parameters, including the threshold voltage and transconductance, are extracted based on experimental data.
View Article and Find Full Text PDFNanoscale
January 2025
Advanced Batteries Research Center, Korea Electronics Technology Institute, 25, Saenari-ro, Seongnam-si, 13509, Republic of Korea.
The SiO electrode interface is passivated with a SiO layer, which hinders the deposition of an inorganic solid electrolyte interphase (SEI) due to its high surface work function and low exchange current density of electrolyte decomposition. Consequently, a thermally vulnerable, organic-based SEI formed on the SiO electrode, leading to poor cycling performance at elevated temperatures. To address this issue, the SEI formation process is thermoelectrochemically activated.
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