HZO thin films deposited by the DPALD and RPALD techniques displayed relatively satisfactory remanent polarization and fatigue endurance, respectively. The ferroelectric memory device function of RPALD-deposited HZO thin films is supported by these findings.
The article scrutinizes the electromagnetic field distortion near rhodium (Rh) and platinum (Pt) transition metals on glass (SiO2) substrates, leveraging finite-difference time-domain (FDTD) mathematical modeling. PND-1186 Evaluated alongside the calculated optical properties of standard SERS metals, such as gold and silver, were the results. Employing the finite-difference time-domain method, we undertook theoretical calculations to examine UV SERS-active nanoparticles (NPs) with structures built from rhodium (Rh) and platinum (Pt) hemispheres and flat surfaces; these contained individual NPs with varying gaps between them. A comparative analysis of the results was undertaken using gold stars, silver spheres, and hexagons as references. The theoretical modeling of single nanoparticles and planar surfaces has illustrated the possibility of achieving optimal light scattering and field enhancement parameters. The presented approach provides a basis for executing the methods of controlled synthesis for LPSR tunable colloidal and planar metal-based biocompatible optical sensors operational within the UV and deep-UV plasmonics domains. The contrast between UV-plasmonic nanoparticles and visible-range plasmonics has been examined and quantified.
The mechanisms of performance degradation in gallium nitride-based metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs), stemming from gamma-ray exposure, were recently found to often utilize extremely thin gate insulators, as detailed in our report. Upon irradiation with the -ray, the device experienced a decline in performance accompanied by total ionizing dose (TID) effects. In this work, the impact of proton irradiation on the device characteristics and its corresponding mechanisms in GaN-based MIS-HEMTs with 5 nm thick Si3N4 and HfO2 gate insulators were examined. Proton irradiation induced variability in the device parameters: threshold voltage, drain current, and transconductance. Employing a 5 nm-thick HfO2 gate insulator resulted in a larger threshold voltage shift compared to using a 5 nm-thick Si3N4 gate insulator, even though the HfO2 insulator showed improved radiation resistance. Differently, the HfO2 gate insulator, at a thickness of 5 nm, presented a diminished reduction in drain current and transconductance. Our systematic research, unlike -ray irradiation, incorporated pulse-mode stress measurements and carrier mobility extraction, demonstrating that proton irradiation in GaN-based MIS-HEMTs simultaneously engendered TID and displacement damage (DD) effects. The degree to which the device's properties changed—threshold voltage shift, drain current, and transconductance—was a consequence of the relative strengths of the TID and DD effects. The device's property modification decreased because of the decline in linear energy transfer, as the energy of the irradiated protons increased. PND-1186 Our research also included a study on the frequency performance degradation of GaN-based MIS-HEMTs due to proton irradiation; the energy of the protons was evaluated in tandem with the extremely thin gate insulator.
This study pioneers the use of -LiAlO2 as a lithium-sequestering positive electrode material to reclaim lithium from aqueous lithium sources. The material's synthesis involved hydrothermal synthesis and air annealing, a process known for its economical and energy-efficient fabrication. Physical characterization demonstrated an -LiAlO2 phase formation within the material, and electrochemical activation indicated the presence of a lithium-deficient AlO2* form capable of lithium ion intercalation. Selective capture of lithium ions was a defining characteristic of the AlO2*/activated carbon electrode pair, observed at concentrations fluctuating between 100 mM and 25 mM. For a 25 mM LiCl mono-salt solution, the adsorption capacity was determined as 825 mg g-1, and energy consumption was recorded at 2798 Wh mol Li-1. Advanced problem-solving within the system encompasses first-pass seawater reverse osmosis brine, where lithium concentration measures slightly above seawater levels, at 0.34 parts per million.
For both fundamental studies and technological applications, manipulating the morphology and composition of semiconductor nano- and micro-structures is of utmost importance. Si-Ge semiconductor nanostructures were constructed on Si substrates, employing photolithographically defined micro-crucibles for the process. The crucial parameter affecting the nanostructure morphology and composition in Ge CVD is the size of the liquid-vapor interface, represented by the micro-crucible opening. Ge crystallites arise within micro-crucibles featuring broader apertures (374-473 m2), whereas no comparable crystallites are present within micro-crucibles possessing openings of only 115 m2. Interface area optimization also yields the production of unique semiconductor nanostructures, including lateral nano-trees in narrow openings and nano-rods in wider openings. TEM imaging confirms that these nanostructures are epitaxially connected to the underlying silicon substrate. The model outlining the micro-scale vapour-liquid-solid (VLS) nucleation and growth's geometrical relationship explains that the incubation time for VLS Ge nucleation is inversely proportional to the size of the opening. Altering the area of the liquid-vapor interface during VLS nucleation provides a means to precisely control the morphology and composition of various lateral nanostructures and microscale structures.
The well-documented neurodegenerative disease Alzheimer's (AD) has witnessed advancements in both neuroscience and Alzheimer's disease-specific research. Progress notwithstanding, no marked enhancement has been seen in available treatments for Alzheimer's. To advance research on AD treatment, AD patient-derived induced pluripotent stem cells (iPSCs) were used to produce cortical brain organoids, showcasing AD symptoms, namely amyloid-beta (Aβ) and hyperphosphorylated tau (p-tau) accumulation. We examined the therapeutic potential of medical-grade mica nanoparticles, STB-MP, for reducing the expression of Alzheimer's disease's key characteristics. In AD organoids, STB-MP treatment, although not preventing pTau expression, did cause a reduction in the build-up of A plaques. STB-MP's intervention seemingly triggered the autophagy pathway via mTOR inhibition, and further decreased -secretase activity by modulating pro-inflammatory cytokine production. In summary, the creation of AD brain organoids effectively replicates the characteristic expressions of AD, thereby establishing it as a promising platform for evaluating novel treatments for Alzheimer's disease.
In this study, we analysed the electron's linear and nonlinear optical characteristics in symmetrical and asymmetrical double quantum wells, which incorporate an internal Gaussian barrier and a harmonic potential, all in the presence of an applied magnetic field. The effective mass and parabolic band approximations form the basis for the calculations. Utilizing the diagonalization method, we identified the eigenvalues and eigenfunctions of an electron trapped within a symmetric and asymmetric double well, created by the sum of a parabolic and Gaussian potential. A density matrix expansion, implemented over two levels, yields the values for linear and third-order nonlinear optical absorption and refractive index coefficients. The proposed model, investigated in this study, is effective for simulating and manipulating optical and electronic characteristics of double quantum heterostructures, both symmetric and asymmetric, specifically double quantum wells and double quantum dots, enabling controllable coupling responses to external magnetic fields.
The metalens, a planar optical element of exceptional thinness, composed of nano-post arrays, is a key component for building compact optical systems that achieve high-performance optical imaging by controlling wavefront modulation. Circularly polarized achromatic metalenses, despite their existence, exhibit a deficiency in focal efficiency, which can be attributed to the nano-posts' low polarization conversion abilities. The practical deployment of the metalens is thwarted by this impediment. Optimization-based topology design methods significantly elevate the degrees of design freedom, thereby enabling the inclusion of nano-post phases and polarization conversion efficiencies in the optimization algorithms simultaneously. Subsequently, it is applied to identify geometrical patterns in nano-posts, ensuring suitable phase dispersions and maximizing the efficiency of polarization conversion. A significant achromatic metalens has a diameter of 40 meters. This metalens exhibits an average focal efficiency of 53% across the 531 nm to 780 nm wavelength spectrum, according to simulation data, thus outperforming previously reported achromatic metalenses with average efficiencies between 20% and 36%. Evaluation reveals that the new method effectively increases the focal effectiveness of the wideband achromatic metalens.
Near the ordering temperatures of quasi-two-dimensional chiral magnets possessing Cnv symmetry and three-dimensional cubic helimagnets, isolated chiral skyrmions are examined within the phenomenological Dzyaloshinskii model. PND-1186 Previously, solitary skyrmions (IS) effortlessly merge with the consistently magnetized condition. A repulsive interaction is observed between these particle-like states at low temperatures (LT), which transforms into an attractive interaction at higher temperatures (HT). Skyrmions are confined to bound states due to a remarkable effect near the ordering temperature. This effect at high temperatures (HT) is a product of the strong coupling between the order parameter's magnitude and its angular component.