In this work, we examine the photoelectrochemical response of TiO.sub.2 layers prepared by reactive DC sputter deposition on conductive glass (FTO). We show that adequate conditioning of the FTO by a ...very thin (few nm thick) Ti interlayer and optimizing the sputter parameters, compact TiO.sub.2 anatase layers can be produced that reach incident photocurrent conversion efficiencies (IPCE) maxima peaking at 75%. This is outperforming many of the best titania photoanode structures (including high surface area 1D and 3D titania structures). The key role of the interlayer is to promote the crystallization of titania in the anatase form during the annealing process (as opposed to rutile in the interlayer-free case). Without this interlayer, an IPCE maxima of almost equal to43% is obtained for otherwise identically processed electrodes. The present work thus describes a most simple straightforward approach for fabricating compact, high-efficiency TiO.sub.2 (anatase) photoanodes.
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 ...MoOsub.3 photodetectors. An ultrathin MoOsub.3/Ir/SiOsub.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/SiOsub.2/Si sample displays a sheet carrier concentration of 5.76 × 10sup.11/cm², which subsequently increases to 6.74 × 10sup.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 MoOsub.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.
During irradiation of dispersion U-Mo/Al fuel, along with the formation of the (U,Mo)Al.sub.x interaction layer, the formation of pores containing gaseous fission products also takes place. Gas pores ...are formed in the fuel particles, in the (U,Mo)Al.sub.x layer and in the aluminum matrix near the (U,Mo)Al.sub.x layer. Usually, the structure of pores is analyzed using optical and scanning electron microscopy, which makes it possible to study only very large pores, those with sizes from tenths of a micron or more. In the present paper, the effect of burnup and isochronous annealing in the 150-580°C temperature range on the change in the substructural characteristics of dispersion U-Mo/Al fuel is established. The values of the characteristics are determined on the basis of experimental data on small-angle neutron scattering. This made it possible to study the substructural characteristics of the fuel in the range of 1 to 50 nanometers.
This paper studies the influence of mechanical tensile loads in the range of 0-300 MPa on the nature of gamma right arrow alpha transformation in cold-rolled maraging steel in the temperature range ...of -20...-60°Ð¡. Based on the kinetic curves of the electrical resistance, critical temperatures M.sub.beg and M.sub.end were determined and the diagrams of the isothermal decomposition of supercooled retained austenite annealed in the two-phase region after two cycles at a temperature of 650°C for 6 h were plotted. It has been established that mechanical loads in the range of 20-300 MPa affect the parameters of the gamma-alpha transformation ambiguously, shifting the isothermal diagrams in temperature and time and significantly changing the stability characteristics of austenite. Resistance of austenite to supercooling T.sub.s varies from -25 to -55°Ð¡, incubation period tau.sub.inc from 2 to 8 min, and decay period tau.sub.dec with two extremes (50 and 100 MPa) from 51 to 518 min depending on the load level. The recorded maximum duration of the annealing austenite decomposition at low loads (20-100 MPa) is explained by the structural and chemical inhomogeneity of the phases, as well as the stress level of the initial state of the samples under study. The threshold stress is determined, loading up to which leads to a decrease by ~15°Ð¡ in the beginning of the gamma right arrow alpha transformation in the interval of subzero temperatures (from -40° to -55°C). It can be assumed that the shift of the diagrams to the range of low temperatures is due to a change in the mechanism of the gamma right arrow alpha transformation. It is shown that cyclic heat treatment in the two-phase region at a temperature of 650°C for 6 h at loads up to 100 MPa delays the isothermal decomposition of supercooled retained austenite in the steel under study.
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.
By means of Rutherford backscattering spectrometry, electron microscopy, and energy-dispersive X-ray spectroscopy, the distribution and interaction of In and As atoms implanted into thermally grown ...SiO.sub.2 films to concentrations of about 1.5 at % are studied in relation to the temperature of subsequent annealing in nitrogen vapors in the range of T = 800-1100°C. It is found that annealing at T = 800-900°C results in the segregation of As atoms at a depth corresponding to the As.sup.+-ion range and in the formation of As nanoclusters that serve as sinks for In atoms. An increase in the annealing temperature to 1100°C yields the segregation of In atoms at the surface of SiO.sub.2 with the simultaneous enhanced diffusion of As atoms. The corresponding diffusion coefficient is D.sub.As = 3.2 x 10.sup.-14 cm.sup.2 s.sup.-1.
Detailed X-ray studies of changes in the structure of terbium orthoborate TbBO.sub.3 in the course of successive high-temperature isothermal annealing of the initial mixture in the form of an ...amorphous precursor and in the form of a homogenized mixture of microcrystalline Tb.sub.7O.sub.12 and B.sub.2O.sub.3 powders have been carried out. It is shown that the formation of TbBO.sub.3 crystals in both cases occurs through the formation of intermediate two-phase states. Particularly, the triclinic high-temperature ν-TbBO.sub.3 phase is formed already at the first crystallization stages (about 600°C) almost simultaneously with the equilibrium vaterite modification of TbBO.sub.3 (sp. gr. P63/mmc) during low-temperature annealing of an amorphous precursor, which transforms into the vaterite modification at an annealing temperature of 850°C. The phase of monoclinic terbium trioxoborate TbB.sub.3O.sub.6 is formed at the first stages of phase formation (about 800°C) almost simultaneously with the vaterite phase when the feedstock is annealed in the form of a homogenized mixture of microcrystalline Tb.sub.7O.sub.12 and B.sub.2O.sub.3 powders. It also transforms into the vaterite modification at an annealing temperature of 950°, which is preserved up to the highest annealing temperatures in the experiment (1200°C). A hypothetical explanation of the formation of such two-phase states during low-temperature annealing of the feedstock and their disappearance at higher annealing temperatures is proposed.
MgB.sub.2 superconductors subjected to deformation under pressure on Bridgeman anvils and subsequent annealings at 800 and 950degreesC were investigated by X-ray diffraction, scanning electron ...microscopy, and microanalysis. It was shown that at these temperatures crystals of MgB.sub.2 phase along the residual boron dissolute in the residual liquid magnesium with the formation of both dense and loose areas of MgB.sub.2 phase. The latter has a negative influence on critical current. At the same time, after these treatments, the samples become more uniform by the phase and chemical composition.
![Kinetics of [gamma] [right ...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1063-7842/small "Kinetics of [gamma] [right arrow] [alpha] Transformation of Retained Austenite in Maraging Steel after Double Annealing at Subzero Temperatures and Loads")
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