Galvanische Abscheidung von Nickel-Chrom-Legierungsschichten. - In: WOMag, ISSN 2195-5891, Bd. 10 (2021), 10, S. 21-24
TU Ilmenau startet DFG-Projekt zur Optimierung von Lithiumionenbatterien. - In: WOMag, ISSN 2195-5891, Bd. 10 (2021), 7/8, S. 13
Zum Stand der Forschung bei chrom(III)-basierten Passivierungen. - In: ZVO-Report, (2021), 1, S. 43
Perspectives of reactive ion etching of silicate glasses for optical microsystems. - In: Journal of optical microsystems, ISSN 2708-5260, Bd. 1 (2021), 4, S. 040901-1-040901-22
We provide a review of the latest research findings as well as the future potential of plasma-based etching technology for the fabrication of micro-optical components and systems. Reactive ion etching (RIE) in combination with lithographic patterning is a well-established technology in the field of micro- and nanofabrication. Nevertheless, practical implementation, especially for plasma-based patterning of complex optical materials such as alumino-silicate glasses or glass-ceramics, is still largely based on technological experience rather than established models. Such models require an in-depth understanding of the underlying chemical and physical processes within the plasma and at the glass-plasma/mask-plasma interfaces. We therefore present results that should pave the way for a better understanding of processes and thus for the extension of RIE processes toward innovative three-dimensional (3D) patterning as well as for the processing of chemically and structurally inhomogeneous silicate-based substrates. To this end, we present and discuss the results of a variety of microstructuring strategies for different application areas with a focus on micro-optics. We consider the requirements for refractive and diffractive micro-optical systems and highlight potentials for 3D dry chemical etching by selective tailoring of the material structure. The results thus provide first steps toward a knowledge-based approach to RIE processing of universal dielectric glass materials for optical microsystems, which also has a significant impact on other microscale applications.
https://doi.org/10.1117/1.JOM.1.4.040901
Simulation verschiedener Hull-Zellen-Geometrien, Teil 1 - spezielle Elektrodengeometrien in 2D und 3D. - In: Galvanotechnik, ISSN 0016-4232, Bd. 112 (2021), 10, S. 1315-1323
A synergetic effect between photogenerated carriers and photothermally enhanced electrochemical urea-assisted hydrogen generation on the Ni-NiO/nickel foam catalyst. - In: Materials advances, ISSN 2633-5409, Bd. 2 (2021), 6, S. 2104-2111
The urea-assisted water electrolysis reactions are of great significance for solving the increasingly serious energy crisis and environmental pollution. Recently, the photo-driven effect strategy has been demonstrated to be an efficient external driving force for improving electrocatalytic activities. Herein, we synthesized Ni-NiO heterostructured nanosheet arrays grown on Ni foam (denoted as Ni-NiO/NF) as a bifunctional electrocatalyst enhancing the urea oxidation reaction (UOR) and hydrogen evolution reaction (HER) activities simultaneously under light irradiation. Moreover, when the catalyst is used in a two-electrode system for the urea-assisted water electrolysis reaction, the cell potential could be reduced to 1.48 V to achieve the current density of 10 mA cm-2 after exposure to light irradiation, as well as remarkable stability. Our studies demonstrate that the enhancement of the HER & UOR activities is attributed to a synergetic effect between photogenerated carriers and photothermy.
https://doi.org/10.1039/D1MA00038A
Tailoring patterned visible-light scattering by silicon photonic crystals. - In: ACS applied materials & interfaces, ISSN 1944-8252, Bd. 13 (2021), 50, S. 60319-60326
Searching for the relationship between the nanostructure and optical properties has always been exciting the researchers in the field of optics (linear optics as well as non-linear optics), energy harvesting (anti-reflective Si solar cells, perovskite solar cells, ..., etc.), and industry (anti-reflection coating on car windows, sunglasses, etc.). In this work, we present an approach for nanostructuring the silicon substrate to silicon photonic crystals. By precisely controlling the etching time and etching path after using nanoimprint lithography, ordered arrays of inverted Si nanopyramids and Si nanopillars with good homogeneity, uniform surface roughness, high reproducibility of pattern transfer, and a controllable aspect ratio are prepared. Experimental investigation of the optical properties indicates that the reflections of these Si nanostructures are mainly determined by the aspect ratio as well as the period of nanostructures. Furthermore, we have experimentally observed visible-light scattering (V-LS) patterns on inverted Si nanopyramids and Si nanopillars, and their corresponding patterns can be precisely controlled by the patterned nanostructures. The V-LS pattern, background, and "ghost peaks" on the angle-resolved scattering results are caused by constructive interference, destructive interference, and the interference situation between both. This controllable nanopatterning on crystalline Si substrates with precisely tunable optical properties shows great potential for applications in many fields, for example, optics, electronics, and energy.
https://doi.org/10.1021/acsami.1c16182
Influence of initial temperature and convective heat loss on the self-propagating reaction in Al/Ni multilayer foils. - In: Materials, ISSN 1996-1944, Bd. 14 (2021), 24, 7815, insges. 15 S.
A two-dimensional numerical model for self-propagating reactions in Al/Ni multilayer foils was developed. It was used to study thermal properties, convective heat loss, and the effect of initial temperature on the self-propagating reaction in Al/Ni multilayer foils. For model adjustments by experimental results, these Al/Ni multilayer foils were fabricated by the magnetron sputtering technique with a 1:1 atomic ratio. Heat of reaction of the fabricated foils was determined employing Differential Scanning Calorimetry (DSC). Self-propagating reaction was initiated by an electrical spark on the surface of the foils. The movement of the reaction front was recorded with a high-speed camera. Activation energy is fitted with these velocity data from the high-speed camera to adjust the numerical model. Calculated reaction front temperature of the self-propagating reaction was compared with the temperature obtained by time-resolved pyrometer measurements. X-ray diffraction results confirmed that all reactants reacted and formed a B2 NiAl phase. Finally, it is predicted that (1) increasing thermal conductivity of the final product increases the reaction front velocity; (2) effect of heat convection losses on reaction characteristics is insignificant, e.g., the foils can maintain their characteristics in water; and (3) with increasing initial temperature of the foils, the reaction front velocity and the reaction temperature increased.
https://doi.org/10.3390/ma14247815
Chemoheteroepitaxy of 3C-SiC(111) on Si(111): influence of predeposited Ge on structure and composition. - In: Physica status solidi, ISSN 1862-6319, Bd. 218 (2021), 24, 2100399, S. 1-10
Secondary ion mass spectroscopy, Fourier transformed infrared spectroscopy, ellipsometry, reflection high energy diffraction and transmission electron microscopy are used to gain inside into the effect of Ge on the formation of ultrathin 3C-SiC layers on Si(111) substrates. Accompanying the experimental investigations with simulations it is found that the ultrathin single crystalline 3C-SiC layer is formed on top of a gradient Si1-x-yGexCy buffer layer due to a complex alloying and alloy decomposition processes promoted by carbon and germanium interdiffusion and SiC nucleation. This approach allows tuning residual stress at very early growth stages as well as the interface properties of the 3C-SiC/Si heterostructure. Useful yields of secondary ions of Ge in Si matrix and Si dimer are estimated.
https://doi.org/10.1002/pssa.202100399
Ultrasensitive strain sensors based on Cu-Al alloy films with voided cluster boundaries. - In: Advanced Materials Technologies, ISSN 2365-709X, Bd. 6 (2021), 12, 2100524, insges. 12 S.
https://doi.org/10.1002/admt.202100524