A5001586703- Glass properties and applications
- Nuclear materials and radiation effects
- Luminescence Properties of Advanced Materials
- Advanced ceramic materials synthesis
- Ferroelectric and Piezoelectric Materials
- Ion-surface interactions and analysis
- Semiconductor materials and devices
- Microwave Dielectric Ceramics Synthesis
- Laser Material Processing Techniques
- Advanced Thermoelectric Materials and Devices
- Integrated Circuits and Semiconductor Failure Analysis
- Phase-change materials and chalcogenides
- Electron and X-Ray Spectroscopy Techniques
- Electronic and Structural Properties of Oxides
- Diamond and Carbon-based Materials Research
- Advanced Surface Polishing Techniques
- Crystal Structures and Properties
- Optical properties and cooling technologies in crystalline materials
- Recycling and utilization of industrial and municipal waste in materials production
- Metal and Thin Film Mechanics
- GaN-based semiconductor devices and materials
- Thermal Expansion and Ionic Conductivity
- Mineralogy and Gemology Studies
- Multiferroics and related materials
- ZnO doping and properties
Fraunhofer Institute for Microstructure of Materials and Systems
2014-2023
Leibniz Institute of Surface Engineering
2004-2021
Advanced Optical Technologies (United States)
2020
Technical University of Munich
2019-2020
Francke Foundations
2015-2019
TU Dresden
2019
LMU Klinikum
2018
Ludwig-Maximilians-Universität München
2018
Urologische Klinik München
2018
Fraunhofer Institute for Mechanics of Materials
2011-2016
Glass-ceramics are noted for their unusual combination of properties and manifold commercialized products consumer specialized markets. Evolution novel glass ceramic processing routes, a plethora new compositions, unique exotic nano- microstructures over the past 60 years led us to review definition glass-ceramics. Well-established emerging methods, such as co-firing, additive manufacturing, laser patterning analyzed concerning core requirements glass-ceramics performance final products. In...
Innovative materials for phosphor converted white light-emitting diodes are in high demand owing to the huge potential of diode technology reduce energy consumption worldwide. As primary blue is already highly optimized, conversion phosphors crucial importance any further improvements. We report on discovery performance red Sr[Li2Al2O2N2]:Eu2+ meeting all requirements a phosphor's optical properties. It combines optimal spectral position phosphor, as defined 2016 Research & Development-plan...
The topography evolution of Si surfaces during low-energy noble-gas ion-beam erosion (ion energy $\ensuremath{\leqslant}2000\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$) at room temperature has been studied. Depending on the parameters, self-organized ripple patterns evolve surface with a wavelength $\ensuremath{\lambda}<100\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. Ripple were found to occur near-normal ion incidence angles...
Growth of nanocrystals precipitated in glasses with specific compositions can be effectively limited by diffusion barriers forming around crystallites. For the first time, we do experimentally prove this concept self-limited growth on nanoscale for a SiO2/Al2O3/Na2O/K2O/BaF2 glass which BaF2 are formed. As shown advanced analytical transmission electron microscopy techniques, these crystals, having great potential photonic applications, is inherently formation ca. 1 nm wide SiO2 shell.
In the glass industry, nucleation agents are broadly used to obtain homogeneously dispersed and nanograined crystals during heat treatment leading ceramics. this paper, role of zirconia titania as in a lithium alumosilicate is studied on nanoscale using cutting edge analytical imaging techniques performed transmission electron microscope. It found that formation ZrTiO4 nanocrystals upon accompanied by diffusion barrier surrounding these precipitates. At interface between residual glass, an...
Nanocrystallization of LaF3 in a glass composition 55SiO2–20Al2O3–15Na2O–10LaF3 (mol%) has been achieved by heat treatment above the transition temperature. A maximum crystal size 14 nm attained, with crystalline fraction and dependent on time temperature thermal treatment. The effect lanthanum fluoride crystallization is noticeable from microstructural compositional changes matrix, which have studied using several techniques, including viscosity, dilatometry, X-ray diffraction, quantitative...
From glasses with the composition 51.9 SiO2·21.2 MgO·21.2 Al2O3·5.7 ZrO2 (in mol %), high and low-quartz solid solution glass ceramics were formed upon heat treatment at 950 °C for different dwell times. A combination of X-ray diffractometry, transmission electron microscopy, scanning microscopy annular dark field imaging energy-dispersive analysis revealed temporal evolution volume crystallization. It is found that crystallization high-quartz nucleated either directly star-shaped...
The crystallisation of the nucleation agent ZrTiO4 in a low thermal-expansion lithium aluminosilicate glass-ceramics is monitored as function time by combining transmission electron microscopy with Ti-L2,3 X-ray absorption near-edge structure spectroscopy. formation liquid–liquid phase-separation droplets shown to precede within latter nanosized droplets. Quantitative data on crystalline fractions enable conclusions self-limited growth nanocrystals and based Avrami's equation, be restricted...
Pattern formation on Si(001) through 2 keV Kr+ ion beam erosion of at an incident angle ϑ=30° and in the presence sputter co-deposition or co-evaporation Fe is investigated by using situ scanning tunneling microscopy, ex atomic force microscopy electron microscopy. The phenomenology pattern presented, experiments are conducted to rule out determine processes relevance with impurities. Special attention given determination morphological phase boundaries their origin. Height fluctuations,...
In recent years, antiferromagnetic spintronics has received much attention since ideal antiferromagnets do not produce stray fields and are more stable to external magnetic compared materials with net magnetization. Akin antiferromagnets, compensated ferrimagnets have zero magnetization but the potential for large spin-polarization strong out of plane anisotropy, and, hence, candidates high density memory applications. Here, we demonstrate that a fully state tunable anisotropy is realized in...
Abstract Glass ceramics based on Li 2 O/Al O 3 /SiO are of high economic importance, as they often show very low coefficients thermal expansion. This enables a number challenging applications, such cooktop panels, furnace windows or telescope mirror blanks. Usually, the crystallization desired LAS crystal phases within glasses must be tailored by careful choice schedule and type nucleation agents to used. The present work describes formation nanocrystalline TiO an base composition that...
Scanning force microscopy (AFM) and high-resolution transmission electron (HRTEM) have been used to investigate the complex topography evolution of Si surfaces during low-energy ion beam erosion. Depending on ion-beam parameters, a variety different topographies can develop surface. At oblique ion-incidence angles, nanodots are formed for energies ⩾300eV upon sample rotation. Properly chosen parameters broad-beam source result in dots possessing very high degree lateral ordering with mean...
Glasses are usually synthesized by quenching a melt rapidly enough to avoid crystallization. Nanocrystalline materials can subsequently be derived from glasses controlled crystallization with applying tailored heat treatment. Upon the latter, nucleation agents widely used adjust desired nanostructures. Nano glass-ceramics often possess intriguing properties. For example, they ultratransparent; that is, hardly scatter light or thermal expansion coefficients very close zero. Such properties...
The influence of the addition 1 mol% Tm 2 O 3 on nanocrystallization LaF in a glass composition 55 SiO –20 Al –15 Na –10 (mol%) has been studied. affects phase separation and delays onset crystallization with respect to undoped glass. Additionally, maximum crystal size is slightly greater than that glass–ceramics. microstructural compositional changes matrix have studied using several techniques, including viscosity, dilatometry, X‐ray neutron diffraction ( XRD , ND ), quantitative Rietveld...