Benzoic and aliphatic carboxylic acid monomolecular layers on oxidized GaAs surface as a tool for two-dimensional photonic crystal infiltration

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Evaporation-driven hydrovoltaics (EDHV) harness the flow of water and interfacial electrokinetic phenomena to convert heat and light into electrical energy, offering a sustainable route to decentralized power generation. Despite promising device demonstrations, progress has been constrained by an incomplete understanding of nanoscale interfacial phenomena and by the lack of predictive design tools. Here, we present a unified experimental, spectroscopic, and theoretical framework that elucidates the coupled

The steel industry generates enormous quantities of iron oxide waste powder (IOWP) from acid regeneration of spent pickling liquor. IOWP is hazardous due to its high acidic and metal compositions, which calls for strategies to safely manage it. In this study, IOWP was utilized in synthesis of magnetite nanoparticles (Fe 3 O 4 NPs) through co-precipitation. The synthesis parameters including NaOH concentration (15–25%), reaction time (1–3 h), and temperature (50–100 °C) were optimized with central composite

Bipolar membranes (BPMs) offer significant potential for electrochemical technologies, especially in CO2 electrolysis. Their unique ability to create pH gradients provides optimum chemical microenvironments at the cathode and anode for efficient, cheap and sustainable CO2 electrolysis. However, state-of-the-art BPMs are limited in their performance due to phenomena such as membrane degradation and membrane dehydration leading to low ionic conductivity, and hence their complete potential for various electroc

Research into mesoscopic magnetic systems, which incorporate magnetic elements with dimensions ranging from a few nm up to a few 10s of micrometer, has been spurred on by the developments in their fabrication, characterisation, and control. Electron beam and optical lithography are key methods for their fabrication because they can be used to create tailor- made planar arrangements of elements or more complex layered structures. These can be further transformed into high quality three-dimensional mesoscale

High-Q silicon nitride (SiN) microresonators enable optical Kerr frequency comb generation on a photonic chip and have recently been shown to support fully coherent combs based on temporal dissipative Kerr soliton formation. For bright soliton formation, it is necessary to operate SiN waveguides in the multimode regime in order to produce waveguide induced anomalous group velocity dispersion. However, this regime can lead to local disturbances of the dispersion due to avoided crossings caused by coupling be

Dynamic wetting phenomena lack of a proper qualitative and quantitative characterization, especially at the micro and nanoscale. The project focuses on the design and fabrication of AFM tips capable of measuring forces and energies involved in wetting phenomena, differentiating between contact line sliding and pinning effects of a fluid interface. The tips geometry consists of micro-sized pillars with a groove all around at middle height. Different fabrication processes were investigated and optimized for t

Capillarity assisted particle assembly (CAPA), is a powerful technique which is gaining in importance. Indeed the application possibilities are vast but, due to its relatively early research stage, the optimal and generic assembly parameters have yet to be investigated. This project aims to set a cornerstone on which to build a reliable and fully regulated CAPA fabrication process. With the current knowledge the issue lies in identifying the transition between optimal accumulation and deposition which often

We report on a home-built detector for catalytic reaction measurements offering good gas isolation from the surrounding ultrahigh vacuum components, high sensitivity for reaction products and a fast response time of 10 ms enabling dynamic studies correlated to reactant gas pulses. The device is mounted in ultrahigh vacuum and combined with a low-temperature scanning tunneling microscope and a source for the deposition of mass-selected clusters. This combination allows for a direct correlation between surfac

We investigated the composition and optical properties of GaInAsN/GaAs single quantum wells (QWs) grown on vicinal-(001) GaAs substrates using metallorganic vapor phase epitaxy with modulated nitrogen-precursor flux. A significant enhancement in N incorporation and photoluminescence efficiency is achieved with such optimized QW structures. Possible mechanisms of the observed increase in N uptake and reduction in defect density, related to the substrate vicinality, are discussed.

An output power up to 5 W at 1.48- m wavelength is achieved from an optically pumped semiconductor disk laser. An active region composed of an AlGaInAs/InP heterostructure grown on an InP substrate was wafer fused with an AlGaAs/GaAs Bragg reflector grown on a GaAs substrate. An intracavity diamond heatspreader bonded to the gain structure surface provides efficient heat removal from the active element. The results further validate that the wafer fusion technique offers a flexible platform for high-power di

During the sliding of an atomic force microscope (AFM) tip on a rough hydrophilic surface, water capillary bridges form between the tip and the asperities of the sample surface. These water bridges give rise to capillary and friction forces. We show that the capillary force increases with the normal load following a 2/3 power law. We trace back this behavior to the load induced change of the tip-surface contact area which determines the number of asperities where the bridges can form. An analytical relation

The oxidn. of nickel gauze catalysts by O2 was investigated by transient response methods. Qual. description of the exptl. transient responses have shown that the oxidn. of metallic nickel proceeds in two stages. The first step is a fast dissocn. of gaseous oxygen on the catalytic surface, followed by oxygen diffusion from the surface into the bulk. This slow second step explains the long tailing obsd. from the exptl. transient responses. Furthermore, a rise of temp. was obsd. during the nickel oxidn. A kin

The metathesis reaction of TeBr4 and AgSb(OTeF5)6 in SO2 led to [TeBr3][Sb(OTeF5)6] and AgBr, and that of 2AgSb(OTeF5)6 with 7Te:TeBr4 led to [Te4][Sb(OTeF5)6]2. The crystal structure of [Cl3Te-F-TeCl3][Sb(OTeF5)6] is reported, prepd. from Te, TeBr4 and AgSb(OTeF5)6 in SO2ClF. [Cl3Te-F-TeCl3][Sb(OTeF5)6] crystallizes in space group P.hivin.1 with a = 10.144(6), b = 10.462(2), c 9.023(4) .ANG., a 93.38(2), b 104.42(4), g 83.06(3) Deg, V = 920.3(5) .ANG.3 and Z = 2. The structure consists of isolated fluoride

Microcrystalline hydrogenated silicon films (muc-Si:H) have been deposited by a high current DC plasma in argon-silane-hydrogen mixtures at growth rates up to 10 nm/s and at substrate temperatures below 500 degreesC. Scanning electron microscopy, X-ray diffraction and FTIR analyses show that these films are highly crystallized. The surface morphology depends strongly on the experimental conditions and varies from a cauliflower structure to a prismatic one. The crystalline orientation of the films also chang

Recent progress made in our lab. in the field of electrochem. promotion of heterogeneous catalytic gas reactions is reviewed. The phenomenon consists of electrochem. polarization of the catalyst/solid electrolyte interface resulting in a dramatic, non-Faradaic modification of the catalytic reaction rate. Two main aspects have been addressed, the mechanistic interpretation of the phenomenon and the development of bipolar cell configurations suitable for practical applications. Fundamental studies were made u

Our investigations focus on low-temperature luminescence experiments on a set of type-II GaAs/AlAs multiple-quantum-well (MQW) samples grown by low-pressure metal-organic vapor-phase epitaxy. The layered structures consists of 50 periods of either 2 monolayers (ML), 4, 5, 6, or 7 ML GaAs embedded in 28 ML AlAs. For (001) GaAs substrates, 6 degrees misoriented towards the nearest (111) plane of group-V atoms, monolayer steps at the AlAs/GaAs interfaces with regular terrace widths (2.7 nm) can be seen by high

The microstructure and preferred orientations of rapid thermally annealed Pb(Zr0.53, Ti0.47)O3 films, deposited on Pt/Ti/SiO2/Si electrode/substrates by solution-gel spinning, have been investigated using analytical and high-resolution electron microscopy and X-ray diffraction. The temperature of pyrolysis of the PZT filMS was found to influence the preferred orientation of the film: lower temperatures (350-degrees-C) favored a (111) orientation, whereas higher temperatures (420-degrees-C) favored a (100) o

Photoemission spectromicroscopy was used to investigate the electronic structure of TiO2 anatase single crystals and polycrystalline thin films. The stoichiometry and the degree of oxidation of as-grown crystals, as-deposited films, as well as of thermally annealed samples in different atmospheres, were analyzed, based on the Ti 2p and O 1s core levels, with an energy resolution of 0.4 eV. The experimental density of states (DOS) was found to be in agreement with the theoretical DOS reported in the literatu

Numerical simulations and experimental results are reported on bistable switching in a semiconductor nonlinear vertical Bragg reflector. An improved structure with an additional linear rear mirror and a phase-adjusting layer was predicted to have lower threshold for bistability than a Fabry-Perot type device. The experimental observation of bistable switching in a nonlinear Bragg reflector is reported. Achieved threshold was comparable with a nonlinear Fabry-Perot device; the simpler structure of a nonlinea

GaAs/AlxGa1-xAs multiple-quantum-well structures with identical well thicknesses (almost-equal-to 119 angstrom) but with different Al contents x in the barrier (x almost-equal-to 0. 1, 0.2, 0.45, and 1) were grown by molecular-beam epitaxy. We report the characterization of the structures by a combination of different techniques. The x-ray-diffraction technique allows us to estimate the Al content x and to measure the period of the structure with good accuracy. Using the photographs given by high-resolution

Benzoic and aliphatic carboxylic acid monomolecular layers on oxidized GaAs surface as a tool for two-dimensional photonic crystal infiltration

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Nanoengineering and Fundamental Insights into Solid-Liquid Interfaces toward Sustainable Energy Applications

Synthesis of magnetite nanoparticles from steel iron oxide waste as a resource recovery strategy: An optimization and characterization study

Water Transport Management in a Bipolar Membrane for CO2 Electrolysis Application

Mesoscopic magnetic systems: From fundamental properties to devices

Higher order mode suppression in high-Q anomalous dispersion SiN microresonators for temporal dissipative Kerr soliton formation

DESIGN, FABRICATION, AND CHARACTERIZATION OF AFM TIPS FOR TENSIONS MEASUREMENT AND MANIPULATION OF FLUID INTERFACES

Investigation of liquid pinning on surface nanoscale topography

An experimental setup combining a highly sensitive detector for reaction products with a mass-selected cluster source and a low-temperature STM for advanced nanocatalysis measurements

High-quality 1.3 lm-wavelength GaInAsN/GaAs quantum wells grown by metalorganic vapor phase epitaxy on vicinal substrates

High-Power 1.48-μm Wafer-Fused Optically Pumped Semiconductor Disk Laser

The 2/3 power law dependence of capillary force on normal load in nanoscopic friction

Mathematical modelling of the unsteady-state oxidation of nickel gauze catalysts

Reactions directed towards Sb(OTeF5)-6 salts of new tellurium cations: formation, FT-Raman spectrum and X-ray crystal structure of [Cl3Te-F-TeCl3][Sb(OTeF5)6] containing the m-fluoro-bis[trichloro-tellurium(IV)] cation

Rapid deposition of hydrogenated microcrystalline silicon by a high current DC discharge

Electrochemical promotion of catalysts for gas phase reactions

Blue luminescence from ultrathin GaAs layers embedded in AlAs

Use of Transmission Electron-Microscopy for the Characterization of Rapid Thermally Annealed, Solution-Gel, Lead-Zirconate-Titanate Films

Electronic-Structure of Anatase TiO2 Oxide

Bistable Switching in a Nonlinear Bragg Reflector

Influence of Al Content in the Barrier on the Optical-Properties of Gaas/Alxga1-Xas(X=0.1-1) Multiple-Quantum-Well Structures