A5032389658- Electronic and Structural Properties of Oxides
- Ferroelectric and Piezoelectric Materials
- Luminescence Properties of Advanced Materials
- Semiconductor materials and devices
- Magnetic and transport properties of perovskites and related materials
- Solid State Laser Technologies
- Photorefractive and Nonlinear Optics
- Glass properties and applications
- Radiation Detection and Scintillator Technologies
- Microwave Dielectric Ceramics Synthesis
- GaN-based semiconductor devices and materials
- Nuclear materials and radiation effects
- Advanced ceramic materials synthesis
- Multiferroics and related materials
- Thermal Expansion and Ionic Conductivity
- Ferroelectric and Negative Capacitance Devices
- Silicon Nanostructures and Photoluminescence
- ZnO doping and properties
- Advanced Condensed Matter Physics
- Atomic and Subatomic Physics Research
- Advanced X-ray and CT Imaging
- Thin-Film Transistor Technologies
- Nuclear Physics and Applications
- Ga2O3 and related materials
- Crystallization and Solubility Studies
Leibniz Institute for Crystal Growth
2016-2025
Stanford University
2014
TU Bergakademie Freiberg
2010
Leibniz Institute for Neurobiology
2008
Sesquioxides are outstanding host materials for rare-earth doped laser gain media. Unfortunately, their very high melting points make it challenging them to be fabricated in quality. Recently, we demonstrated that some mixed sesquioxides exhibit significantly reduced temperatures compared constituents. This enables growth by the established Czochralski method yielding of optical Due inhomogeneously broadened spectra caused intrinsic disorder, promising generation and amplification ultrashort...
60 and 120 nm thick epitaxial films of isotopically enriched bcc iron (α-57Fe) grown on (100) MgO substrates are studied using x-ray diffraction, reflection high-energy electron diffraction (RHEED), conversion Mössbauer spectroscopy (CEMS). X-ray RHEED data indicate that each film behaves as a single crystal material consistent with the relative intensity ratios spectral lines observed in CEMS spectrum. Data further confirm easy axis magnetization lies along ⟨100⟩ family directions cubic...
This investigation showcases the viability of producing SixGe1−x bulk single crystals via Czochralski technique. A high Si content in Ge-rich SiGe wafers is highly desirable for various applications quantum technology, particularly as strain-relaxed buffers realization hole spin qubits strained Ge well heterostructures. The focus lies on crystal growth such materials and their chemical structural quality. For this, process, starting from a pure seed melt, utilizing continuous feeding by...
The elastic behavior of Sr1.03Ga10.81Mg0.58Zr0.58O19 and Pr-doped SrAl12O19 single crystals grown by the top-seeded solution growth technique was investigated resonant ultrasound spectroscopy at temperatures between 103 1573 K. coefficients thermal expansion were obtained high-resolution dilatometry in same temperature range. Values for bulk moduli ambient are 206.5 181.0 GPa Sr1.03Ga10.81Mg0.58Zr0.58O19, respectively. aluminate possesses higher values mean stiffness compared to gallate,...
The optical absorption edge and near infrared of SrTiO were measured at temperatures from 4 to 1703 K. decreases 3.25 eV K 1.8 is extrapolated approximately 1.2 the melting point (2350 K). transmission in IR rapidly above 1400 because free carrier about 50% room temperature value 1673 carriers are generated by thermal excitation electrons over band gap formation charged vacancies. observed temperature-dependent can be well reproduced a calculation based on simple models for intrinsic...
Abstract SnO 2 is a semiconductor with wide optical bandgap (3.5 eV), which makes it an attractive transparent semiconducting oxide (TSO) for electronic and opto‐electronic applications. At elevated temperatures is, however, much more unstable than other TSOs (such as ZnO, Ga O 3 , or In ). This leads to rapid decomposition even under very high oxygen pressures. Our experiments showed that stoichiometric does not melt up 2100 °C, in contradiction earlier published data. Bulk single crystals,...
Cubic rare-earth sesquioxide crystals are strongly demanded host materials for high power lasers, but due to their melting points investigations on thermodynamics and the growth of large-size optical quality remain a challenge. Detailed thermal ternary system Lu 2 O 3 –Sc –Y revealing large range compositions with temperatures below 2200°C minimum 2053°C composition (Sc 0.45 Y 0.55 ) presented. These reduced enable first time mixed disordered structure by conventional Czochralski method from...
We report on the identification of a tri-carbon defect in AlN bulk crystals grown by physical vapor transport. The gives rise to single infrared absorption line at 1769 cm−1 unintentionally carbon doped crystals. This splits into eight lines enriched with isotope 13C. observed patterns can unambiguously be assigned local vibrational mode that contains exactly three atoms. most probable arrangement atoms is nearest-neighbor substitutional sites, replacing two nitrogen and one aluminum atom,...
We present the first-time growth of bulk BaSnO3 single crystals from melt by direct solidification, their basic electrical and optical properties as well structural quality. Our measurement melting point (MP) amounts to 1855 °C ± 25 K. At this temperature an intensive decomposition non-stoichiometric evaporation takes place partial pressure SnO(g) is about 90 times higher than that BaO(g). X ray powder diffraction identified only perovskite phase, while narrow rocking curves having a full...
In the research work described here, single-crystalline SrTiO 3 has been used as a model system to facilitate development of new qualitative characterization method for nondestructive identification small-angle boundaries in bulk single crystals. Subgrain misorientations with lower limit range between 40 and 100′′ were reliably identified. For scientists engineers working field single-crystal growth it is often indispensable continuously check structural quality grown crystals, which usually...
Terbium titanate (Tb<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>) is a spin-ice material with remarkable magneto-optical properties.
We demonstrate the growth of large (Mg,Zr):SrGa12O19 (SGMZ) single crystals and use a combination X-ray imaging techniques to analyze their structural chemical homogeneity. Single-crystal cylinders with lengths diameters up about 2.5 cm are achieved. Our characterization polished sections reveals localized (0001) facet that is typically formed at center interface. Such facets seen as key factor limiting large-area excellent quality due local deviations in segregation behavior dopants....
Synthetic rubies were grown by the optical floating zone method and characterized cathodoluminescence (CL) microscopy spectroscopy in combination with microprobe analysis. The measured intensity of Cr3+-induced CL corundum is influenced different parameters such as sample thickness orientation, beam current, quality surface. Furthermore, spectral distribution emission changes concentrations Cr structure. Due to these effects, it usually not possible estimate content directly using intensity....
Cylindrical SrTiO3 bulk single crystals with diameters of about 15 mm and lengths between 13 50 were grown from stoichiometric melts by the edge-defined film fed growth (EFG) method. Typical average etch pit density values are in range 1.7–2.0 × 105 cm−2. Rocking curve measurements revealed FWHM 28′′ 41′′. Suitable conditions for puck-shaped also found Czochralski (Cz) However, structural quality was lower as compared to EFG So far pulling melt using method suffered instabilities like...