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One-dimensional negative thermal expansion material has important applications in thermal expansion control and fiber toughened composite. Orthorhombic Al.sub.1.6Sc.sub.0.4Mo.sub.3O.sub.12 nanofibers have been prepared by electrospinning. The phase composition, microstructure, morphology, and thermal expansion performance of the samples prepared at various temperatures were investigated. Results show that as-prepared Al.sub.1.6Sc.sub.0.4Mo.sub.3O.sub.12 nanofibers are smooth and homogeneous with a fiber diameter of about 370.00 nm, but they show an amorphous structure. Orthorhombic Al.sub.1.6Sc.sub.0.4Mo.sub.3O.sub.12 nanofibers can be obtained at 550 â with a diameter of around 140.00 nm. With the increase of post-annealing temperatures, the crystallization of the samples was improved. However, higher post-annealing temperatures will destroy the nanofiber structure of the samples. HTXRD reveals that orthorhombic Al.sub.1.6Sc.sub.0.4Mo.sub.3O.sub.12 nanofibers show anisotropic NTE in 25-700 °C. The expansion coefficients [alpha].sub.a, [alpha].sub.b, and [alpha].sub.c of Al.sub.1.6Sc.sub.0.4Mo.sub.3O.sub.12 nanofibers are -5.05 x 10.sup.-6 °C.sup.-1, 4.41 x 10.sup.-6 °C.sup.-1, and -3.18 x 10.sup.-6 °C.sup.-1, respectively. The [alpha].sub.v is -3.83 x 10.sup.-6 °C.sup.-1, and the corresponding [alpha].sub.l is -1.28 x 10.sup.-6 °C.sup.-1.

β-Ga[sub.2]O[sub.3] is an ultra-wide bandgap semiconductor (E[sub.g]~4.8 eV) of interest for many applications, including optoelectronics. Undoped Ga[sub.2]O[sub.3] emits light in the UV range that can be tuned to the visible region of the spectrum by rare earth dopants. In this work, we investigate the crystal lattice recovery of (2¯01)-oriented β-Ga[sub.2]O[sub.3] crystals implanted with Yb ions to the fluence of 1 ×10[sup.14] at/cm[sup.2]. Post-implantation annealing at a range of temperature and different atmospheres was used to investigate the β-Ga[sub.2]O[sub.3] crystal structure recovery and optical activation of Yb ions. Ion implantation is a renowned technique used for material doping, but in spite of its many advantages such as the controlled introduction of dopants in concentrations exceeding the solubility limits, it also causes damage to the crystal lattice, which strongly influences the optical response from the material. In this work, post-implantation defects in β-Ga[sub.2]O[sub.3]:Yb crystals, their transformation, and the recovery of the crystal lattice after thermal treatment have been investigated by channeling Rutherford backscattering spectrometry (RBS/c) supported by McChasy simulations, and the optical response was tested. It has been shown that post-implantation annealing at temperatures of 700–900 °C results in partial crystal lattice recovery, but it is accompanied by the out-diffusion of Yb ions toward the surface if the annealing temperature and time exceed 800 °C and 10 min, respectively. High-temperature implantation at 500–900 °C strongly limits post-implantation damage to the crystal lattice, but it does not cause the intense luminescence of Yb ions. This suggests that the recovery of the crystal lattice is not a sufficient condition for strong rare-earth photoluminescence at room temperature and that oxygen annealing is beneficial for intense infrared luminescence compared to other tested environments.

Surface plasmon technology is regarded as having significant potential for the enhancement of the performance of 2D oxide semiconductors, especially in terms of improving the light absorption of 2D MoO[sub.3] photodetectors. An ultrathin MoO[sub.3]/Ir/SiO[sub.2]/Si heterojunction Schottky self-powered photodetector is introduced here to showcase positive photoconductivity. In wafer-scale production, the initial un-annealed Mo/2 nm Ir/SiO[sub.2]/Si sample displays a sheet carrier concentration of 5.76 × 10[sup.11]/cm², which subsequently increases to 6.74 × 10[sup.12]/cm² after annealing treatment, showing a negative photoconductivity behavior at a 0 V bias voltage. This suggests that annealing enhances the diffusion of Ir into the MoO[sub.3] layer, resulting in an increased phonon scattering probability and, consequently, an extension of the negative photoconductivity behavior. This underscores the significance of negative photoconductive devices in the realm of optoelectronic applications.

Post-growth rapid thermal annealing of [alpha]-MoO.sub.3 layered crystals in Pb-species that were in situ evaporated from PbO coatings has been studied using various techniques. They reveal the occurrence of solid-gas reactions between MoO.sub.3 and PbO, which is accompanied by MoO.sub.3 sublimations, leading to remarkable morphology and structure evolutions when the annealing temperature (T.sub.ann) is increased from 400 to 800 °C. Onset of nucleation and crystal growth of PbMoO.sub.4, which initiated at the structural defects of [alpha]-MoO.sub.3, occurred at 600 °C. The growth of PbMoO.sub.4 and the consumption of MoO.sub.3 at their boundary areas give rise to materials melting over there at 700 °C, which, in turn, connected the localized grown PbMoO.sub.4 via capillary actions. After cooling down to room temperature, the PbMoO.sub.4 solidified in crystals, while the MoO.sub.3 consisted of both amorphous and crystalline precipitates with regular in-plane orientations. In comparison, spherical domes that appeared at T.sub.ann = 800 °C resulted from enhanced localized reactions between the molten PbMoO.sub.4/MoO.sub.3 and the Al.sub.2O.sub.3 substrate. These results shed new lights on thermal behavior of [alpha]-MoO.sub.3 and the temperature-dependent reactions between MoO.sub.3 and PbO.

The properties of Mo/B.sub.4C multilayer X-ray mirrors with periods of 3.74-3.84 nm are studied in this work. The dependences of the transmission band, reflection coefficient and the magnitude of internal stresses in mirrors on the ratio of material thicknesses in the period were investigated. The results of a study of the effect of thermal annealing on the structural parameters and reflective characteristics of mirrors are also presented in the paper.

This work is devoted to the study of the luminescence inhomogeneity nature of bulk (Ga.sub.xAl.sub.1-x).sub.2O.sub.3 samples grown by the Czochralski method. In the study of sample cleavages by the local cathodoluminescence method, regions with different luminescence were observed. To determine the cathodoluminescence contrast nature, we studied the uniformity of the aluminum distribution, the surface topography, and compared the luminescence spectra and the kinetics of emission bands for different regions of the sample. Also, to determine the luminescence bands nature, the crystal was annealed in air at 1000°C. This made it possible to observe the change in luminescence for the same region of the sample. Based on the studies performed, it was concluded that inhomogeneous luminescence is associated with the distribution of point defects. Upon annealing in air, the transformation of nonradiative recombination centers into luminescent centers was observed.

Gallium oxide (Ga[sub.2]O[sub.3]), an ultrawide bandgap semiconductor, is an ideal material for solar-blind photodetectors, but challenges such as low responsivity and response speed persist. In this paper, one-dimensional (1D) Ga[sub.2]O[sub.3] nanorods were designed to achieve high photodetection performance due to their effective light absorption and light field confinement. Through modulating source concentration, pH value, temperature, and reaction time, 1D β-Ga[sub.2]O[sub.3] nanorods were controllably fabricated using a cost-effective hydrothermal method, followed by post-annealing. The nanorods had a diameter of ~500 nm, length from 0.5 to 3 μm, and structure from nanorods to spindles, indicating that different β-Ga[sub.2]O[sub.3] nanorods can be utilized controllably through tuning reaction parameters. The 1D β-Ga[sub.2]O[sub.3] nanorods with a high length-to-diameter ratio were chosen to construct metal-semiconductor-metal type photodetectors. These devices exhibited a high responsivity of 8.0 × 10[sup.−4] A/W and detectivity of 4.58 × 10[sup.9] Jones under 254 nm light irradiation. The findings highlighted the potential of 1D Ga[sub.2]O[sub.3] nanostructures for high-performance solar-blind ultraviolet photodetectors, paving the way for future integrable deep ultraviolet optoelectronic devices.

The impact of thermal annealing under temperature alteration on the wetting and mechanical attributes of Fe[sub.3]Si films built through facing target sputtering (FTS) is an essential topic for study in order to identify their characteristics under varying temperatures. Consequently, we introduced a thermal annealing process in a vacuum for two hours under varying temperatures of 300, 600, and 900 °C to our Fe[sub.3]Si films created via FTS. The primary purpose of this current research is to examine the effect of the thermal annealing technique under temperature alteration on the wetting and mechanical traits of Fe[sub.3]Si films. In this research, Fe[sub.3]Si films were built onto the Si wafer by FTS and divided for use in thermal annealing under temperature alteration. The structural, morphological, wetting, and mechanical traits of the Fe[sub.3]Si films under thermal annealing are provided in the present work. Based on our information, this work represents an original study on the change in wetting and mechanical traits of Fe[sub.3]Si films through thermal annealing under temperature alteration.

Vacancy-mediated transport drives the functionality of oxide-based nonvolatile memristive devices. Here, we report the size dependence of TiO.sub.2/Nb:STO heterojunctions for electroforming and the subsequent resistive switching process. Conductive AFM measurements suggest that the forming and reset voltages both decrease with increasing junction size. We also show oxygen flow ratio changes during fabrication, and post-annealing impacts the set voltage and resistance ratio through changes in available oxygen vacancies. Finally, a polarity reversal between eight-wise and counter-eight-wise switching occurs after vacuum and ambient anneals, thus modulating oxygen vacancy availability and changing (reversibly) the mechanism from vacancy migration to an electron trap/detrap process.

The development of novel manufacturing techniques of nano-/micromaterials, especially metallodielectric materials, has enabled dynamic development of such fields as nanoplasmonics. However, the fabrication methods are still mostly based on time-consuming and costly top-down techniques limited to two-dimensional materials. Recently, directional solidification has been proposed and utilized for manufacturing of volumetric nanoplasmonic materials using the example of a Bi.sub.2O.sub.3-Ag eutectic-based nanocomposite. Here, we explain the evolution of silver in this composite, from the crystal growth through the post-growth annealing processes. Investigation with tunneling electron microscopy shows that silver initially enters the composite as an amorphous AgBiO.sub.3 phase, which is formed as a wetting layer between the grains of Bi.sub.2O.sub.3 primary phase. The post-growth annealing leads to decomposition of the amorphous phase into Bi.sub.2O.sub.3 nanocrystals and intergranular Ag nanoparticles, providing the tunable localized surface plasmon resonance at yellow light wavelengths.