A5040923751- Metal and Thin Film Mechanics
- Semiconductor materials and devices
- Chalcogenide Semiconductor Thin Films
- Semiconductor materials and interfaces
- Quantum Dots Synthesis And Properties
- Semiconductor Quantum Structures and Devices
- GaN-based semiconductor devices and materials
- Advanced ceramic materials synthesis
- Integrated Circuits and Semiconductor Failure Analysis
- Nanowire Synthesis and Applications
- Photonic and Optical Devices
- Mechanical Behavior of Composites
- Diamond and Carbon-based Materials Research
- Microstructure and mechanical properties
- Electronic Packaging and Soldering Technologies
- Electron and X-Ray Spectroscopy Techniques
- Mechanical stress and fatigue analysis
- Copper-based nanomaterials and applications
- High-Temperature Coating Behaviors
- Force Microscopy Techniques and Applications
- Advanced Electron Microscopy Techniques and Applications
- Copper Interconnects and Reliability
- Bone health and osteoporosis research
- Advanced Sensor and Energy Harvesting Materials
- Numerical methods in engineering
Siemens (Austria)
2023-2024
Infineon Technologies (Austria)
2023-2024
University of California, Santa Barbara
2017-2023
Swiss Federal Laboratories for Materials Science and Technology
2015-2021
Durham University
2012-2017
University of New Mexico
2016
Erich Schmid Institute of Materials Science
2009-2013
Austrian Academy of Sciences
2009-2013
University of Liverpool
2012
Montanuniversität Leoben
2009-2011
Research in electric double-layer capacitors (EDLCs) and rechargeable batteries is converging to target systems that have battery-level energy density capacitor-level cycling stability power density. This research direction has been facilitated by the use of redox-active electrolytes add faradaic charge storage increase EDLCs. Aqueous redox-enhanced electrochemical (redox ECs) have, however, performed poorly due cross-diffusion soluble redox couples, reduced cycle life, low operating...
Cathodoluminescence is used to measure the recombination velocity of heterointerfaces between Cu2ZnSnS4 (CZTS) and CuxSnySz, SnS secondary phases precipitated along grain boundaries as well ZnS within CZTS interiors. The CZTS/CuxSnySz CZTS/ZnS had velocities smaller than bulk carrier diffusion while opposite true for CZTS/SnS heterointerface. Secondary having crystal structures compatible with (e.g., ZnS, Cu2SnS3) are likely form small misfit strain hence low interfacial velocity....
With recent developments in high‐speed and high‐power electronics Si‐based photonic integration, the concept of monolithic III–V/Si integration through epitaxial methods is gaining momentum. However, performance reliability epitaxially grown devices are still limited by defects semiconductor material, especially threading dislocation density (TDD). Herein, a novel “asymmetric step‐graded filter” structure molecular beam epitaxy (MBE) proposed based on systematic study commonly used...
We report direct growth of 1550-nm InGaAsP multi-quantum-well (MQW) structures in densely packed, smooth, highly crystalline, and millimeter-long InP nanoridges grown by metalorganic chemical vapor deposition on silicon-on-insulator (SOI) substrates. Aspect-ratio-trapping selective area techniques were combined with a two-step process to obtain good material quality as revealed photoluminescence, scanning electronic microscopy, high-resolution X-ray diffraction characterization. Transmission...
A leading hypothesis for silver nanoparticle biosynthesis suggests that the enzyme nitrate reductase plays a key role in process, assisted by coenzyme nicotinamide adenine dinucleotide phosphate (NADPH). Here, we show NADPH alone can act as reducing agent of salt to form nanoparticles. In fact, addition during synthesis causes decrease reaction rate and broadening size distribution particles. The NADPH-synthesized particles were monodispersed with mean radius 5.1 ± 1.0 nm, indicated...
Epitaxially integrated III-V semiconductor lasers for silicon photonics have the potential to dramatically transform information networks, but currently, dislocations limit performance and reliability even in defect tolerant InAs quantum dot (QD) based lasers. Despite being below critical thickness, QD layers these devices contain previously unexplained misfit dislocations, which facilitate non-radiative recombination. We demonstrate here that form during post-growth cooldown due combined...
New emerging technologies in the field of flexible electronic devices require that metal films adhere well and flex with polymer substrates. Common thin film materials used for these applications include copper (Cu) an adhesion interlayer chromium (Cr). Copper can be quite ductile easily move substrate. However, Cr is more brittle fractures at lower strains than Cu. This study aims to examine fracture subsequent buckling delamination strained on polyimide (PI). In-situ scanning electron...
The chemical reactivity and/or the diffusion of Ag atoms or ions during thermal processing can cause irreversible structural damage, hindering application nanowires (NWs) in transparent conducting films and other applications that make use material's nanoscale properties. Here, we describe a simple effective method for growing monolayer SnO2 on surface under ambient conditions, which protects from damage. Our results show Sn2+ undergo redox reaction presence water. First-principle...
Abstract The article addresses effects of silicate deposit composition on reactions with yttrium monosilicate (YMS), a candidate environmental barrier coating for aero‐engine components. Computed phase equilibria are used to predict the nature and relative proportions reaction products extent YMS consumption upon twelve deposits varying at 1300°C. These predictions compared results corresponding experimental study three exemplary deposits. Although sequence formed (typically apatite...
Rapid progress in the performance of organic devices has increased demand for advances technology thin-film permeation barriers and understanding failure mechanisms these material systems. Herein, we report extensive study mechanical gas barrier properties Al₂O₃/ZnO nanolaminate films prepared on substrates by atomic layer deposition (ALD). Nanolaminates single compound around 250 nm thickness were deposited polyethylene terephthalate (PET) foils ALD at 90 °C using trimethylaluminium (TMA)...
We investigated the electrical and optical performances of semipolar (11-22) InGaN green µLEDs with a size ranging from 20 × µm2 to 100 µm2, grown on low defect density large area GaN template patterned sapphire substrate. Atom probe tomography (APT) gave insights quantum wells (QWs) thickness indium composition indicated that no clusters were observed in QWs. The showed small wavelength blueshift 5 nm, as current increased 90 A/cm2 exhibited size-independent EQE 2% by sidewall passivation...
Titanium layers are used to promote adhesion between polymer substrates for flexible electronics and the Cu or Au conducting lines. Good of lines in circuits is critical improving circuit performance increasingcircuit lifetime. Nominally 50 nm thick Ti films on polyimide (PI) investigated by fragmentation testing under uniaxial tensile load as-deposited state, at 350 °C, after annealing. The cracking buckling show clear differences thermally treated samples, cracks much straighter buckles...
We report the development of gallium arsenide (GaAs) films grown on V-groove patterned (001) silicon (Si) by metalorganic chemical vapor deposition. This technique can provide an advanced virtual substrate platform for photonic integrated circuits Si. A low defect density 9.1 × 106 cm−2 was achieved with aspect ratio trapping capability V-grooved Si and dislocation filtering approaches including thermal cycle annealing filter layers. The efficiencies these reduction methods are quantified...
The role of threading dislocations in the intrinsic degradation lateral GaN devices during high reverse bias stress tests (RBSTs) is largely unknown. We now present results on p-GaN/AlGaN/2DEG heterojunctions with a width 200 μm GaN-on-Si. A time-dependent permanent heterojunction under and elevated temperatures can be observed, ultimately leading to hard breakdown device destruction. By using an integrated series p-GaN resistor, protected from destruction and, consequently, influence...