The main goal of the carried out tests was to analyze the influence of the surface modification of a substrate by depositing composite ZnO layers by the Atomic Layer Deposition (ALD) method. The samples were subjected to preliminary surface modification consisting of being sandblasted and electropolished. A ZnO layer was applied to the prepared substrates by the ALD method. As a precursor of ZnO, diethylzinc (DEZ) was used, which reacted with water, enabling the deposition of the thin films. The chamber temperature was as follows: T = 100–300 °C. The number of cycles was 500 and 1500. As part of the assessment of the physicochemical properties of the resulting surface layers, the tests of chemical composition of the layer, pitting corrosion, impedance corrosion, adhesion to the metal substrate, morphology surface, and wettability were carried out. On the basis of the obtained research, it was found that a composite ZnO layer deposited onto a substrate previously subjected to the electrochemical polishing process has more favorable physicochemical properties. Moreover, an influence of temperature and the number of cycles of the deposition process on the obtained properties was observed, where the ZnO layer was characterized by more favorable properties at a temperature of 200–300 °C at 1500 cycles of the deposition process.
The essential device for optical computing is an all-optical transistor in which a weak “gate” light controls the strong “source” light. Particularly promising for application in logic operations are all-optical transistors using quasiparticles in a semiconductor because they can be easily integrated into circuits in a way similar to that of conventional electronic ones. However, the practical development of such devices has so far been limited due to extreme difficulties in achieving room temperature operation. In this work, we proposed and numerically verified a scheme of the high-temperature stable all-optical transistor, where light controls light by using deep-level defects in non-polar InGaN/GaN heterostructure and photo-exited holes as an intermediate medium. The developed optical switching concept fulfills all criteria for the useful all-optical transistor listed in Miller, Nat. Photonics 4, 3 (2010), in particular fan-out and cascadability, which are the most difficult to meet. For the design of our transistor, we applied an entirely new approach to III-nitride device physics: we turned usually undesirable deep-level defects into a key, active element of the transistor in which they realize on and off operations. Due to this, the developed device was able to obtain excellent operation stability in a wide temperature range up to 500 K as well as an extremely high on/off ratio (106) and gain (100). Finally, in order to show that the proposed transistor concept is feasible, we performed the gated-photoluminescence experiment for metal–oxide–semiconductor GaN structures.
The use of implants made out of metallic materials can cause some negative effects that reduce the effectiveness of treatment of various diseases of the human circulatory system. These include, above all, blood clotting on the surface and insufficient hemocompatibility [1]. To reduce these negative effects, the formation of physical and chemical properties of the surface layer of the implants are indicated [2]. The paper proposes the use of the atomic layer deposition method to form a surface layer with participation of a suitable silicon morphology. One of the basic criteria of hemocompatibility of implants is their corrosion resistance. Therefore, in assessing the SiO2 layer, a detailed test for resistance to corrosion by potentiodynamic and impedance studies were conducted, including the process of steam sterilization under pressure. The chemical structure of the surface layer was also evaluated. The results clearly demonstrated that the applied layer of SiO2 has better corrosion resistance when compared to the steel substrate. This reduces excessive transfer of iron, chromium, nickel and molybdenum into the blood. On the other hand, studies of the chemical composition of the depth profile showed a diffuse SiO2 layer which results in a better adhesion to the substrate. Die Verwendung von Implantaten aus metallischen Materialien kann einige negative Auswirkungen haben, die die Wirksamkeit der Behandlung verschiedener Erkrankungen des menschlichen Kreislaufsystems verringern. Dazu gehören vor allem Blutgerinnsel an der Oberfläche und ungenügende Hämokompatibilität [1]. Um diese negativen Effekte zu reduzieren, wird die Ausbildung der physikalischen und chemischen Eigenschaften der Oberflächenschicht der Implantate angegeben [2]. Es wird die Verwendung des Atomlagenabscheidungs-Verfahrens vorgeschlagen, um eine Oberflächenschicht unter Beteiligung einer geeigneten Silicium-Morphologie zu bilden. Eines der Hauptkriterien für die Hämokompatibilität von Implantaten ist ihre Korrosionsbeständigkeit. Daher wurde bei der Beurteilung der SiO2-Schicht ein komplexer Test auf Korrosionsbeständigkeit durch Potenzialdynamik und Impedanzuntersuchungen durchgeführt, einschließlich des Prozesses der Dampfsterilisation unter Druck. Die chemische Struktur der Oberflächenschicht wurde ebenfalls bewertet. Die Ergebnisse zeigten deutlich, dass die aufgebrachte SiO2-Schicht im Vergleich zum Stahlsubstrat eine bessere Korrosionsbeständigkeit aufweist. Dies reduziert eine übermäßige Übertragung von Eisen, Chrom, Nickel und Molybdän in das Blut. Auf der anderen Seite zeigten die Untersuchungen der chemischen Zusammensetzung des Tiefenprofils eine diffuse SiO2-Schicht, die zu einer besseren Haftung an dem Substrat führt.
The aim of this work was to investigate the possibility of modifying the physical properties of indium tin oxide (ITO) layers by annealing them in different atmospheres and temperatures. Samples were annealed in vacuum, air, oxygen, nitrogen, carbon dioxide and a mixture of nitrogen with hydrogen (NHM) at temperatures from 200 °C to 400 °C. Annealing impact on the crystal structure, optical, electrical, thermal and thermoelectric properties was examined. It has been found from XRD measurements that for samples annealed in air, nitrogen and NHM at 400 °C, the In2O3/In4Sn3O12 share ratio decreased, resulting in a significant increase of the In4Sn3O12 phase. The annealing at the highest temperature in air and nitrogen resulted in larger grains and the mean grain size increase, while vacuum, NHM and carbon dioxide atmospheres caused the decrease in the mean grain size. The post-processing in vacuum and oxidizing atmospheres effected in a drop in optical bandgap and poor electrical properties. The carbon dioxide seems to be an optimal atmosphere to obtain good TE generator parameters—high ZT. The general conclusion is that annealing in different atmospheres allows for controlled changes in the structure and physical properties of ITO layers.
