Low-temperature Annealing Conditions Research Articles

Fabrication of a Three-Dimensional Microfluidic System from Poly(methyl methacrylate) (PMMA) Using an Intermiscibility Vacuum Bonding Technique.

In this study, the fabrication of microfluidic chips through the bonding of poly (methyl methacrylate) (PMMA) boards featuring designed patterns to create a three-dimensional sandwich structure with embedded microchannels was explored. A key focus was optimization of the interface quality of bonded PMMA pairs by adjusting the solvent, such as such as acetone, alcohol, and their mixture. Annealing was conducted below 50 °C to leverage the advantages of low-temperature bonding. Because of the differences in the chemical reactivity of PMMA toward acetone, alcohol, and their combinations, the resulting defect densities at the bonding interfaces differed significantly under low-temperature annealing conditions. To achieve the optimal sealing integrity, bonding pressures of 30 N, 40 N, and 50 N were evaluated. The interface was analyzed through microstructural examination via optical microscopy and stress measurements were determined using digital photoelasticity, while the bonding strength was assessed through tensile testing.

Work function tunning of lithium-doped vanadium oxide for functioning as hole injection layer in organic light-emitting diodes

The hole-injection layer (HIL) plays an important role in the electroluminescent property of organic light-emitting diodes (OLEDs). In this paper, Li-doped VOx was prepared by solution processing under low-temperature annealing conditions and used as a new kind of HIL in OLEDs. It demonstrated the best phosphorescent OLED performance when the molar ratio of Li:VOx was 3%. The turn-on voltage was 3.7 V, the maximum current efficiency (CE) was 69.5 cd A−1 and the maximum power efficiency (PE) was 48.4 lm∙W−1. In contrast to the OLEDs with pristine VOx as HIL, the CE and PE of the OLEDs with Li:VOx were increased by 14.7% and 40.7% respectively. Based on the Fowler-Nordheim tunneling mechanism, doping Li+ in VOx improved the efficiency of hole injection and balanced carriers by adjusting the work function, thereby improving the efficiency of the device. The experimental results indicated that Li-doped VOx film prepared by solution processing is a very potential material as the HIL of high-performance OLED.

Highly self-diffused Sn doping in α-Fe2O3 nanorod photoanodes initiated from β-FeOOH nanorod/FTO by hydrogen treatment for solar water oxidation.

In this study, we present an advanced strategy of low-temperature hydrogen annealing combined with high- temperature quenching in air for activating α-Fe2O3 nanorod photoanodes to boost the photoelectrochemical performance. We report that various low-temperature annealing conditions (340, 360, 380, and 400 °C) under hydrogen gas flow convert β-FeOOH into magnetite (Fe3O4) as well as introduce Sn4+ diffusion from FTO substrates to its surface. Furthermore, high-temperature quenching (800 °C) resulted in the phase change of magnetite (Fe3O4) into hematite (α-Fe2O3) and self Sn4+ doping into the hematite lattice. Thus, the hydrogen-assisted thermally activated hematite photoanode achieved a photocurrent density of 1.35 mA cm-2 at 1.23 V vs. RHE and 1.91 mA cm-2 at 1.4 V vs. RHE, which is 70% and 80% higher than that of directly quenched hematite at 800 °C. These combined two step strategies provide new insight into high Sn-self doping for α-Fe2O3 photoanodes and allow for further development of more efficient solar water oxidation systems.

Selective formation of apical oxygen vacancies in La2−xSrxCuO4

The superconducting properties of high-\tc\ materials are functions of carriers concentration, which is controlled by the concentration of defects including heterovalent cations, interstitial oxygen ions, and oxygen vacancies. Here we combine low-temperature thermal treatment of La$_{2-x}$Sr$_{x}$CuO$_{4}$ epitaxial thin films and confocal Raman spectroscopy to control and investigate oxygen vacancies. We demonstrate that the apical site is the most favorable position to accommodate oxygen vacancies under low-temperature annealing conditions. Additionally we show that in high-quality films of overdoped La$_{2-x}$Sr$_{x}$CuO$_{4}$, oxygen vacancies strongly deform the oxygen environment around the copper ions. This observation is consistent with previous defect-chemical studies, and calls for further investigation of the defect induced properties in the overdoped regime of the hole-doped lanthanum cuprates.

Microhardness and phase composition of TiO y /hydroxyapatite nanocomposites synthesized under low-temperature annealing conditions

We have prepared a dispersion-hardened composite material based on hydroxyapatite (HAP) and nonstoichiometric titanium monoxide (TiOy). To this end, substoichiometric titanium monoxide (y < 1; 10 or 20 wt %) was added to HAP precipitated from solution. After heat treatment, pure HAP and HAP containing 10 and 20 wt % TiO0.92 differed in the behavior of their microhardness. The addition of TiO0.92 lowers the hardening onset temperature of the composite material by several hundred degrees Celsius. Annealing at 600°C leads to the formation of the Ti4.5O5 and Ti6O11 phases in the composite containing 20 wt % TiO0.92.

Processing line for industrial radiation-thermal synthesis of doped lithium ferrite powders

The paper considers the issues of industrial production of doped lithium ferrite powders by radiation-thermal method. A technological scheme of the processing line is suggested. The radiation-thermal technological scheme enables production of powders with technical characteristics close to the required ones under relatively low temperature annealing conditions without intermediate mixing. The optimal conditions of the radiation-thermal synthesis are achieved isothermally under irradiation by the electron beam with energy of 2.5 MeV in the temperature range of 700-750 0C within- 120 min.

Phase transformations in YBa2Cu3O y (y ≤ 6.5) under low-temperature treatment

The influence of low-temperature annealing conditions on the properties and structure of YBa2Cu3O y (123) with y ≤ 6.5 has been investigated. It has been shown that, at T = 200°C, the transition to the orthorhombic phase and the separation into phases with different oxygen concentrations occur slowly. With an increase in the temperature, the rate of phase transformations increases significantly. The phase transition of tetragonal YBa2Cu3O6.3 to the orthorhombic phase due to the oxygen ordering leads to the appearance of superconductivity. There is a direct evidence that, at temperatures T ≤ 300°C in the absence of water vapor, the 123 compound is separated into phases with different oxygen concentrations. The phase separation is accompanied by the formation of an oxygen-enriched phase with a critical temperature T c ≈ 90 K (at T = 200°C) or T c ≈ 76 K (at T = 300°C). The presence of water vapor in the low-temperature annealing atmosphere significantly accelerates all the processes occurring in the system; however, the incorporation of water into the structure of the 123 compound leads to its transition into the 124-type phase.

Cu-Fe-P 系希薄合金の低温焼鈍硬化に及ぼすクラスタの影響

It is well known that low temperature anneal-hardening (LTAH) appears in highly alloyed copper such as a Cu-30 mass%Zn alloy. On the other hand, it has been said that the LTAH could not emerge in a dilute alloy even if with a greater reduction during cold rolling. Therefore, the effect of alloying concentrations of order 0.1 mass% on the LTAH behavior has been hardly discussed. In this work, changes of material properties and microstructure in a Cu-0.12 mass%Fe-0.04 mass%P alloy during low temperature annealing after cold rolling up to 90% were investigated. The LTAH appeared under a limited combination of cold rolling and low temperature annealing conditions. In the surface region hardened by the LTAH, the dislocation density decreased by half whereas the volume fraction of Fe-P clusters quadrupled, compared with the condition before low temperature annealing. The estimated change in hardness due to the combination of dislocation hardening and elastic strain hardening is in reasonably good agreement with the experimental increase in Vickers hardness.

Improvement of Characteristics in Highly Reliable thin Film Diode with Anodic Tantalum Pentoxide by Low Temperature Annealing Conditions

AbstractIn this study, the quality of thin film diode (TFD) as a switching device for active-matrix liquid-crystal-displays (AM-LCDs) was enhanced by low temperature annealing conditions with high reliability and good electrical properties. Device was composed with Ta as bottom electrode, anodic Ta2O5 as insulator layer and top electrode. Two types of material such as Ti and Cr were evaluated as a top electrode of the TFD device to optimize the symmetry of current-voltage characteristic curve, respectively. The annealing was done at low temperature conditions below 350°C. The low temperature annealing improved the TFD device with nearly perfect symmetry under high electric field.

The use of RAPDs for the analysis of parasites.

There is a lack of sequence information concerning polymorphic loci in parasite genomes. Thus, the use of arbitrary PCR primers under low temperature annealing conditions to generate random amplified polymorphic DNAs (RAPDs) represents an important approach to the study of the structure of parasite populations, their genetic variation as well as improved diagnosis of the diseases they cause. Following the examination of all variables and their effect on the reproducibility of the reaction, we have established a protocol for the analysis of RAPDs that involves amplification at two separate DNA concentrations followed by polyacrylamide gel electrophoresis and silver staining. We find the technique to be sensitive, reproducible, simple and relatively cheap. It has already provided insight into the genetic variation in populations of schistosomes and trypanosomes and is being used to study various other endemic infections. We also use specific primers under low stringency conditions in situations where the objective of the amplification is the detection of a particular sequence and where normal high stringency conditions give a positive/negative answer such as sex determination or diagnosis of blood born infections. Under low stringency conditions, specific amplification products persist but products of low stringency priming are also apparent and serve as a perfect internal control for negative samples.

Stable and unstable surface state charge in thermally oxidized silicon

Two types of instabilities in MOS devices, occurring under the influence of a negative voltage bias on the metal electrode, can be observed by cooling under bias, from a temperature at which the bias was applied, to 77 K. In this paper we report on these effects as a function of oxidation temperature and ambient and of annealing treatments. The results suggest that the centres causing these instabilities are related to the centres causing the fixed oxide charge. It will be shown that the fast interface state density and the amount of fixed oxide charge depend on the low-temperature annealing conditions as well as on the geometry of the Aluminum-gate. This may explain the discrepancy found in the literature about the value of the fixed oxide charge as a function of oxidation temperature.