Yttrium Doping Effects on Ferroelectricity and Electric Properties of As-Deposited Hf1-xZrxO2 Thin Films via Atomic Layer Deposition.

Hf1-xZrxO2 (HZO) thin films are versatile materials suitable for advanced ferroelectric semiconductor devices. Previous studies have shown that the ferroelectricity of HZO thin films can be stabilized by doping them with group III elements at low concentrations. While doping with Y improves the ferroelectric properties, there has been limited research on Y-HZO thin films fabricated using atomic layer deposition (ALD). In this study, we investigated the effects of Y-doping cycles on the ferroelectric and electrical properties of as-deposited Y-HZO thin films with varying compositions fabricated through ALD. The Y-HZO thin films were stably crystallized without the need for post-thermal treatment and exhibited transition behavior depending on the Y-doping cycle and initial composition ratio of the HZO thin films. These Y-HZO thin films offer several advantages, including enhanced dielectric constant, leakage current density, and improved endurance. Moreover, the optimized Y-doping cycle induced a phase transformation that resulted in Y-HZO thin films with improved ferroelectric properties, exhibiting stable behavior without fatigue for up to 1010 cycles. These as-deposited Y-HZO thin films show promise for applications in semiconductor devices that require high ferroelectric properties, excellent electrical properties, and reliable performance with a low thermal budget.

Stratum-Confined Solid-State Reaction (SC-SSR) toward Colloidal Silicon-Based Hollow Nanostructures for Bioapplications.

Silicon nanostructures (SiNSs) can provide multifaceted bioapplications; but preserving their subhundred nm size during high-temperature silica-to-silicon conversion is the major bottleneck. The SC-SSR utilizes an interior metal-silicide stratum space at a predetermined radial distance inside silica nanosphere to guide the magnesiothermic reduction reaction (MTR)-mediated synthesis of hollow and porous SiNSs. In depth mechanistic study explores solid-to-hollow transformation encompassing predefined radial boundary through the participation of metal-silicide species directing the in-situ formed Si-phase accumulation within the narrow stratum. Evolving thin-porous Si-shell remains well protected by the in-situ segregated MgO emerging as a protective cast against the heat-induced deformation and interparticle sintering. Retrieved hydrophilic SiNSs (<100 nm) can be conveniently processed in different biomedia as colloidal solutions and endocytosized inside cells as photoluminescence (PL)-based bioimaging probes. Inside the cell, rattle-like SiNSs encapsulated with Pd nanocrystals can function as biorthogonal nanoreactors to catalyze intracellular synthesis of probe molecules through C-C cross coupling reaction.

Ghost-Template-Faceted Synthesis of Tunable Amorphous Hollow Silica Nanostructures and Their Ordered Mesoscale Assembly.

Despite the enormous applications of and fundamental scientific interest in amorphous hollow-silica nanostructures (h-SiNSs), their synthesis in crystal-like nonspherical polygonal architectures is challenging. Herein, we present a facile one-shot synthetic procedure for various unconventional h-SiNSs with controllable surface curvatures (concave, convex, or angular), symmetries (spherical, polygonal, or Janus), and interior architectures (open or closed walls) by the addition of a metal salt and implementing kinetic handles of silica precursor (silanes/ammonia) concentrations and reverse-micellar volume. During the silica growth, we identified the key role of transiently in situ crystallized metal coordination complexes as a nanopolyhedral "ghost template", which provides facet-selective interactions with amino-silica monomers and guides the differential silica growth that produces different h-SiNSs. Additionally, crystal-like well-defined polygonal h-SiNSs with flat surfaces, assembled as highly ordered close-packed octahedral mesoscale materials (ca. 3 µm) where h-SiNSs with different nanoarchitectures act as building units (ca. 150 nm) to construct customizable cavities and nanospaces, differ from conventionally assembled materials.

Combined Treatment with Low-Level Laser and rhBMP-2 Promotes Differentiation and Mineralization of Osteoblastic Cells under Hypoxic Stress.

BACKGROUND: The aim of this study was to evaluate the combined effect of low-level laser treatment (LLLT) and recombinant human bone morphological protein-2 (rhBMP-2) applied to hypoxic-cultured MC3T3-E1 osteoblastic cells and to determine possible signaling pathways underlying differentiation and mineralization of osteoblasts under hypoxia. METHODS: MC3T3-E1 cells were cultured under 1% oxygen tension for 72 h. Cell cultures were divided into four groups: normoxia control, low-level laser (LLL) alone, rhBMP-2 combined with LLLT, and rhBMP-2 under hypoxia. Laser irradiation was applied at 0, 24, and 48 h. Cells were treated with rhBMP-2 at 50 ng/mL. Alkaline phosphatase activity was measured at 3, 7, and 14 days to evaluate osteoblastic differentiation. Cell mineralization was determined with Alizarin red S staining at 7 and 14 days. Western blot assays were performed to evaluate whether p38/protein kinase D (PKD) signaling was involved. RESULTS: The results indicate that LLLT and rhBMP-2 synergistically increased alkaline phosphatase (ALP) activity and mineralization. Western blot analyses showed that expression of type I collagen, runt-related transcription factor 2 (RUNX2), and Osterix (Osx), increased and expression of hypoxia-inducible factor 1-alpha (HIF-1α), decreased more in the LLLT and rhBMP-2 combined group than in the rhBMP-2 or LLL alone groups. Moreover, LLLT and rhBMP-2 stimulated p38 phosphorylation and rhBMP-2 and LLLT increased Prkd1 phosphorylation. CONCLUSION: Combined treatment with rhBMP-2 and LLL induced differentiation and mineralization of hypoxic-cultured MC3T3-E1 osteoblasts by activating p38/PKD signaling in vitro.

A Hybrid Gate Dielectrics of Ion Gel with Ultra-Thin Passivation Layer for High-Performance Transistors Based on Two-Dimensional Semiconductor Channels.

We propose a hybrid gate structure for ion gel dielectrics using an ultra-thin Al2O3 passivation layer for realizing high-performance devices based on electric-double-layer capacitors. Electric-double-layer transistors can be applied to practical devices with flexibility and transparency as well as research on the fundamental physical properties of channel materials; however, they suffer from inherent unwanted leakage currents between electrodes, especially for channel materials with low off-currents. Therefore, the Al2O3 passivation layer was introduced between the metal electrodes and ion gel film as a leakage current barrier; this simple approach effectively reduced the leakage current without capacitance degradation. In addition, we confirmed that a monolayer MoS2 transistor fabricated with the proposed hybrid gate dielectric exhibited remarkably enhanced device properties compared to a transistor using a normal ion gel gate dielectric. Our findings on a simple method to improve the leakage current properties of ion gels could be applied extensively to realize high-performance electric-double-layer transistors utilizing various channel materials.

High speed image space parallel processing for computer-generated integral imaging system.

In an integral imaging display, the computer-generated integral imaging method has been widely used to create the elemental images from a given three-dimensional object data. Long processing time, however, has been problematic especially when the three-dimensional object data set or the number of the elemental lenses are large. In this paper, we propose an image space parallel processing method, which is implemented by using Open Computer Language (OpenCL) for rapid generation of the elemental images sets from large three-dimensional volume data. Using the proposed technique, it is possible to realize a real-time interactive integral imaging display system for 3D volume data constructed from computational tomography (CT) or magnetic resonance imaging (MRI) data.

Modulation of physical properties of polyvinylsiloxane impression materials by filler type combination.

Polyvinylsiloxanes (PVS), used as dental impression materials, were formulated with the variation of loading combination of six types of fillers including nano-sized fumed silica. The fillers were blended with three types of silicone polymers together with cross-linker and inhibitor in base paste and with plasticizer and platinum catalyst in catalyst paste. By replacing parts of crystalline quartz with other fillers, the setting time became much faster. The test group in which quarter of quartz was replaced with fumed silica showed the most ideal working and setting time for clinical use. There was a negative correlation between pH and setting time (p < 0.05). Combining the fumed silica was effective in increasing the viscosity, tensile strength and maximum% strain. Combining the diatomaceous earth reduced the setting time and maximum% strain, and dramatically increased the viscosity and tensile strength. The best modulation of physical properties of PVS material was possible by combining fillers during the formulation.