A5041965145- Electronic and Structural Properties of Oxides
- Magnetic and transport properties of perovskites and related materials
- Ferroelectric and Piezoelectric Materials
- Silicon Nanostructures and Photoluminescence
- Phase-change materials and chalcogenides
- Metallic Glasses and Amorphous Alloys
- Diamond and Carbon-based Materials Research
- ZnO doping and properties
- Ga2O3 and related materials
- Luminescence Properties of Advanced Materials
- Thin-Film Transistor Technologies
- High Temperature Alloys and Creep
- nanoparticles nucleation surface interactions
- Silicon and Solar Cell Technologies
- Semiconductor materials and devices
- Microstructure and mechanical properties
- Advanced Materials Characterization Techniques
Tokyo Institute of Technology
2016-2020
Imperial College London
2016-2017
University of Stuttgart
2012-2014
Max Planck Institute for Intelligent Systems
2014
Max Planck Society
2014
The high room temperature mobility and the electron effective mass in ${\mathrm{BaSnO}}_{3}$ are investigated depth by evaluation of free carrier absorption observed infrared spectra for epitaxial films with concentrations from $8.3\ifmmode\times\else\texttimes\fi{}{10}^{18}$ to $7.6\ifmmode\times\else\texttimes\fi{}{10}^{20}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$. Both optical band gap widening conduction filling scattering mechanisms low- high-doping regimes consistently...
Epitaxial transparent oxide NixMg1-xO (0 ≤ x 1) thin films were grown on MgO(100) substrates by pulsed laser deposition. High-resolution synchrotron X-ray diffraction and high-resolution transmission electron microscopy analysis indicate that the are compositionally structurally homogeneous, forming a completely miscible solid solution. Nevertheless, composition dependence of optical band gap shows strong non-parabolic bowing with discontinuity at dilute NiO concentrations < 0.037. Density...
GeO$_2$ has an $\alpha$-quartz-type crystal structure with a very wide fundamental band gap of 6.6 eV and is good insulator. Here we find that the stable rutile-GeO$_2$ polymorph 4.6 surprisingly low $\sim$6.8 ionization potential, as predicted from alignment using first-principles calculations. Because short O$-$O distances in rutile containing cations small effective ionic radii such Ge$^{4+}$, antibonding interaction between O 2p orbitals raises valence maximum energy level to extent hole...
This work presents the solid phase epitaxial growth of high mobility La:BaSnO3 thin films on SrTiO3 single crystal substrates by crystallization through thermal annealing nanocrystalline prepared pulsed laser deposition at room temperature. The show quality and Hall mobilities up to 26 ± 1 cm2/Vs. Secondary ion mass spectroscopy is used determine La concentration profile in films, a 9%–16% doping activation efficiency obtained. An investigation H BaSnO3 presented employing plasma treatment...
Cubic perovskite oxides are emerging high-mobility transparent conducting (TCOs), but Ge-based TCOs had not been known until the discovery of metastable cubic ${\mathrm{SrGeO}}_{3}$. $0.5\ifmmode\times\else\texttimes\fi{}0.4\ifmmode\times\else\texttimes\fi{}0.2\text{\ensuremath{-}}\mathrm{m}{\mathrm{m}}^{3}$ large single crystals ${\mathrm{SrGeO}}_{3}$ were successfully synthesized employing high-pressure flux method. The phonon spectrum is determined from IR optical reflectance and...
By tackling the challenge of extending transparent oxide semiconductors to Ge based oxides, we have found a not-yet-reported crystal structure, named $\beta$-SrGe$_2$O$_5$, which is composed edge-sharing GeO$_6$ octahedra interconnected by GeO$_5$ bipyramids. Single crystals were successfully grown high-pressure flux method. $\beta$-SrGe$_2$O$_5$ has band gap 5.2 eV and dispersive conduction with an effective mass as small 0.34 times electron rest mass, originates from network. Although...