A5063576647- Geology and Paleoclimatology Research
- Geological and Geochemical Analysis
- Cryospheric studies and observations
- Geological Studies and Exploration
- Polar Research and Ecology
- Geochemistry and Geologic Mapping
- Paleontology and Stratigraphy of Fossils
- ZnO doping and properties
- Landslides and related hazards
- Methane Hydrates and Related Phenomena
- earthquake and tectonic studies
- Winter Sports Injuries and Performance
- High-pressure geophysics and materials
- Hydrocarbon exploration and reservoir analysis
- Geological formations and processes
- Ga2O3 and related materials
- Climate change and permafrost
- Copper-based nanomaterials and applications
- Geological and Geophysical Studies
- GaN-based semiconductor devices and materials
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- Ion-surface interactions and analysis
- Arctic and Antarctic ice dynamics
- Pleistocene-Era Hominins and Archaeology
Federal Institute for Geosciences and Natural Resources
2016-2025
Justus-Liebig-Universität Gießen
2008-2013
Leipzig University
2010
Technical University of Munich
2009
Goethe University Frankfurt
2001-2006
Several regions in the High Arctic still lingered poorly explored for a variety of mineralization types because harsh climate environments and remoteness. Inglefield Land is an ice-free region northwest Greenland that contains copper-gold associated with hydrothermal alteration mineral assemblages. In this study, Landsat-8, Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER), WorldView-3 multispectral remote sensing data were used mapping prospecting at regional, local,...
Listvenites normally form during hydrothermal/metasomatic alteration of mafic and ultramafic rocks represent a key indicator for the occurrence ore mineralizations in orogenic systems. Hydrothermal/metasomatic mineral assemblages are one significant indicators damage zones major tectonic boundaries, which can be detected using multispectral satellite remote sensing data. In this research, Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) data were used to detect listvenite...
Using photoelectron spectroscopy, we investigate the band alignments of Cu2O/ZnO heterointerface and compare findings with corresponding values for Cu2O/GaN. While Cu2O/ZnO, find a valence offset (VBO) 2.17 eV conduction (CBO) 0.97 eV, both are considerably reduced Cu2O/GaN where numbers 1.47 0.24 (CBO), respectively. The large CBO between ZnO Cu2O will very likely result in low photovoltaic power conversion efficiencies as is current status solar cells.
Wurtzite Zn1−xMgxO thin films with Mg contents between x=0 and x=0.37 were grown on c-plane sapphire substrates by plasma assisted molecular beam epitaxy using a MgO/ZnMgO buffer layer. The a-lattice parameter is independent from the concentration, whereas c-lattice decreases 5.20 Å for to 5.17 x=0.37, indicating pseudomorphic growth. near band edge photoluminescence shows blueshift increasing concentration an emission energy of 4.11 eV x=0.37. Simultaneously, energetic position deep defect...
The optical properties of GaN nanowires grown by catalyst free plasma-assisted molecular beam epitaxy on Si (111) are investigated photoluminescence (PL) spectroscopy. influence the Si- and Mg-flux as well III-V ratio during growth PL is discussed. Mg concentration determined secondary ion mass spectroscopy ranges from 5×1018 to 1×1020 cm−3. Raman scattering reveals that strain-free, irrespective or Mg-doping. near band-edge emission undoped slightly Si-doped material dominated narrow D0X...
We report on the effect of Mg doping properties GaN nanowires grown by plasma assisted molecular beam epitaxy. The most significant feature is presence triple-twin domains, density which increases with increasing concentration. resulting high concentration misplaced atoms gives rise to local changes in crystal structure equivalent insertion three non-relaxed zinc-blende (ZB) atomic cells, result quantum wells along wurtzite (WZ) nanowire growth axis. High resolution electron energy loss...
Abstract Cu 2 O thin films were grown on sapphire (0001) and MgO (100) substrates by chemical vapor deposition. The crystalline, vibrational electrical properties of the layers amount incorporated background impurities have been examined. X‐ray diffraction measurements revealed, that polycrystalline grew in (111) orientation MgO. Raman indicated presence CuO inclusions films. are dominated an acceptor level located 150 meV above valence band. This may originate from unintentionally silicon...
One of Earth’s most fundamental climate shifts, the greenhouse-icehouse transition 34 million years ago, initiated Antarctic ice sheet buildup, influencing global until today. However, extent during Early Oligocene Glacial Maximum (~33.7 to 33.2 ago) that immediately followed this transition—a critical knowledge gap for assessing feedbacks between permanently glaciated areas and early Cenozoic reorganization—is uncertain. In work, we present shallow-marine drilling data constraining earliest...
We report on the optical properties of nitrogen acceptor-doped ZnO epilayers in medium and high doping regimes using temperature excitation power-dependent, as well time-resolved photoluminescence experiments. The were doped with ammonia during homoepitaxial growth single-crystal substrates different surface polarities. Significant differences characteristics are observed between nonpolar $a$-plane, polar $c$-plane Zn-face O-face substrates, which demonstrates incorporation acceptor...
In Antarctica, spectral mapping of altered minerals is very challenging due to the remoteness and inaccessibility poorly exposed outcrops. This investigation evaluates capability Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) satellite remote sensing imagery for discrimination phyllosilicate mineral groups in Antarctic environment northern Victoria Land. The Mixture-Tuned Matched-Filtering (MTMF) Constrained Energy Minimization (CEM) algorithms were used detect sub-pixel...
Research Article| October 01, 2013 The Mesozoic Victoria Basin: Vanished link between Antarctica and Australia Frank Lisker; Lisker 1Department of Geosciences, University Bremen, PF 330 440, 28334 Germany Search for other works by this author on: GSW Google Scholar Andreas L. Läufer 2Federal Institute Geosciences Natural Resources (BGR), Stilleweg 2, 30655 Hannover, Geology (2013) 41 (10): 1043–1046. https://doi.org/10.1130/G33409.1 Article history received: 13 Mar 2012 rev-recd: 25 May...
New U-Pb zircon ages for the younger phase of magmatism in Sør Rondane Mountains (East Antarctica) are combined with published igneous and metamorphic show evidence at least four thermal pulses: 650–600 Ma, 580–550 ca. 530 a magmatic tail between 510 500 Ma. No than Ma have been found, contrast to situation central western Dronning Maud Land. Zircon Lu-Hf isotopic data best explained as reflecting both crustal reworking juvenile input, latter more obvious during period. The Hf data, together...
Abstract The shape of ice shelf cavities are a major source uncertainty in understanding ice‐ocean interactions. This limits assessments the response Antarctic sheets to climate change. Here we use vibroseis seismic reflection surveys map bathymetry beneath Ekström Ice Shelf, Dronning Maud Land. new reveals an inland‐sloping trough, reaching depths 1,100 m below sea level, near current grounding line, which attribute erosion by palaeo‐ice streams. trough does not cross‐cut outer parts...
Svalbard's Northwestern Basement Province is traditionally divided into the Albert I Land and Biscayarhalvøya terranes. New U–Pb age data on zircon monazite structural geochemical provide first evidence of early Paleozoic deposits south Terrane indicating possible existence a third terrane: Germaniahalvøya Terrane. This area represented by Cambro-Ordovician succession mica schist marble (Lernerøyane Group) its higher-grade metamorphic equivalent (Liefdefjorden Migmatite Complex), which were...
Most ice sheet models indicate that the Antarctic Ice Sheet (AIS) will lose considerable amounts of over coming decades and centuries. This mass loss mainly be caused by warm deep waters increasingly reaching AIS’ margins and, with many upstream parts ice-sheet sectors being grounded far below modern sea level, this lead to accelerating irreversible retreat. Are we therefore currently witnessing initiation runaway retreat large result in rapid level rise resulting severe...