A5065306244- Graphene research and applications
- Organic Electronics and Photovoltaics
- Quantum and electron transport phenomena
- Conducting polymers and applications
- Thin-Film Transistor Technologies
- Carbon Nanotubes in Composites
- Molecular Junctions and Nanostructures
- Topological Materials and Phenomena
- Nanowire Synthesis and Applications
- Semiconductor materials and devices
- Advanced Memory and Neural Computing
- 2D Materials and Applications
- Organic Light-Emitting Diodes Research
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Advanced Sensor and Energy Harvesting Materials
- ZnO doping and properties
- Perovskite Materials and Applications
- Advancements in Battery Materials
- Force Microscopy Techniques and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Metal-Organic Frameworks: Synthesis and Applications
- Electronic and Structural Properties of Oxides
- Mechanical and Optical Resonators
- Semiconductor materials and interfaces
University of Göttingen
2020-2025
Czech Academy of Sciences, Institute of Physics
2025
Ludwig-Maximilians-Universität München
2016-2023
International Center for Advanced Studies
2023
Center for NanoScience
2017-2022
Nanosystems Initiative Munich
2017-2022
Munich Center for Quantum Science and Technology
2019-2022
The University of Sydney
2021
Karlsruhe Institute of Technology
2021
Donostia International Physics Center
2021
Individual graphene oxide sheets subjected to chemical reduction were electrically characterized as a function of temperature and external electric fields. The fully reduced monolayers exhibited conductivities ranging between 0.05 2 S/cm field effect mobilities 2−200 cm2/Vs at room temperature. Temperature-dependent electrical measurements Raman spectroscopic investigations suggest that charge transport occurs via variable range hopping intact islands with sizes on the order several...
The non-interacting energy spectrum of graphene and its bilayer counterpart consists multiple degeneracies owing to the inherent spin, valley layer symmetries. Interactions among charge carriers are expected spontaneously break these symmetries, leading gapped ordered states. In quantum Hall regime states predicted be ferromagnetic in nature whereby system becomes spin polarized, polarized or both. graphene, due parabolic dispersion, interaction-induced symmetry breaking is already at zero...
We study the near-field optical behavior of Fabry-Pérot resonances in thin metal nanowires, also referred to as quasi one-dimensional plasmonic nanoantennas. From eigenmodes well beyond quadrupolar order we extract both, propagation constant and reflection phase guided surface plasmon polariton with superb accuracy. The combined symmetry breaking effects oblique illumination retardation allow excitation dipole forbidden, even resonances. All measurements are supported by rigorous simulations...
The primary driver for the development of organic thin-film transistors (TFTs) over past few decades has been prospect electronics applications on unconventional substrates requiring low-temperature processing. A key requirement many such is high-frequency switching or amplification at low operating voltages provided by lithium-ion batteries (~3 V). To date, however, most organic-TFT technologies show limited dynamic performance unless high are applied to mitigate contact resistances and...
Five core-cyanated perylene carboxylic diimides end-functionalized with fluorine-containing linear and cyclic substituents have been synthesized employed in the fabrication of air-stable n-channel organic thin-film field-effect transistors carrier mobilities up to 0.1 cm2/Vs. The relationships between molecular structure, morphology, substrate temperature during vacuum deposition, transistor performance, air stability investigated. Our experiments led us conclude that role fluorine...
The application of graphene in electronic devices requires large scale epitaxial growth. presence the substrate, however, usually reduces charge carrier mobility considerably. We show that it is possible to decouple partially sp3-hybridized first graphitic layer formed on Si-terminated face silicon carbide from substrate by gold intercalation, leading a completely sp2-hybridized with improved properties.
We report on the unexpected finding of nanoscale fibers with a diameter down to 25 nm that emerge from polymer solution during standard spin-coating process. The fiber formation relies upon Raleigh−Taylor instability spin-coated liquid film arises due competition centrifugal force and Laplace induced by surface curvature. This procedure offers an attractive alternative electrospinning for efficient, simple, nozzle-free fabrication variety solutions.
Bilayer graphene has attracted considerable interest due to the important role played by many-body effects, particularly at low energies. Here we report local compressibility measurements of a suspended bilayer. We find that energy gaps filling factors ν= ± 4 do not vanish fields, but instead merge into an incompressible region near charge neutrality point zero electric and magnetic field. These results indicate existence zero-field ordered state are consistent with formation either...
The mechanisms behind the threshold-voltage shift in organic transistors due to functionalizing of gate dielectric with self-assembled monolayers (SAMs) are still under debate. We address by which SAMs determine threshold voltage, analyzing whether voltage depends on gate-dielectric capacitance. have investigated based five oxide thicknesses and two rather diverse chemical properties, using benchmark semiconductor dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene. Unlike several previous...
The alignment of organic semiconductors (OSCs) in the active layers electronic devices can confer desirable properties, such as enhanced charge transport properties due to better ordering, anisotropy for reduced device cross-talk, and polarized light emission or absorption. solution-based deposition highly aligned small molecule OSCs has been widely demonstrated, but polymeric thin films deposited directly from solution typically required surface templating complex pre- postdeposition...
Semiconducting organic films that are at the heart of light-emitting diodes, solar cells and transistors frequently contain a large number morphological defects, most prominently interconnects between crystalline regions. These grain boundaries can dominate overall (opto-)electronic properties entire device their exact energetic nature is still under current debate. Here, we explore in detail energetics novel electron conductive perylene diimide thin film. Via combination temperature...
Abstract In organic thin‐film transistors (TFTs) fabricated in the inverted (bottom‐gate) device structure, surface roughness of gate dielectric onto which organic‐semiconductor layer is deposited expected to have a significant effect on TFT characteristics. To quantitatively evaluate this effect, method tune consisting thin aluminum oxide and an alkylphosphonic acid self‐assembled monolayer over wide range by controlling single process parameter, namely substrate temperature during...
The development of layer-oriented two-dimensional conjugated metal–organic frameworks (2D c-MOFs) enables access to direct charge transport, dial-in lateral/vertical electronic devices, and the unveiling transport mechanisms but remains a significant synthetic challenge. Here we report novel synthesis metal-phthalocyanine-based p-type semiconducting 2D c-MOF films (Cu2[PcM–O8], M = Cu or Fe) with an unprecedented edge-on layer orientation at air/water interface. structure formation is guided...
Electrolyte-gated organic transistors (EGOTs) are promising candidates as a new class of neuromorphic devices in hardware-based artificial neural networks that can outperform their complementary metal oxide semiconductor (CMOS) counterparts regarding processing speed and energy consumption. Several ways which to implement such exist, two prominent methods be implemented by nanoscopic vertical EGOTs, we show here. First, electrolyte-gated with donor-acceptor diketopyrrolopyrrole-terthiophene...
One of the circuit topologies for implementation unipolar integrated circuits (circuits that use either p-channel or n-channel transistors, but not both) is zero-VGS architecture. Zero-VGS often provide excellent static performance (large small-signal gain and large noise margins), they suffer from signal delay imposed by load transistor. To address this limitation, we have used electron-beam lithography to fabricate based on organic transistors with channel lengths as small 120 nm flexible...
Abstract Bernal bilayer graphene (BLG) offers a highly flexible platform for tuning the band structure, featuring two distinct regimes. One is tunable gap induced by large displacement fields. Another gapless metallic occurring at low fields, rich fine structure consisting of four linearly dispersing Dirac cones and van Hove singularities. Even though BLG has been extensively studied experimentally, evidence this still elusive, likely due to insufficient energy resolution. Here, we use...
In two-dimensional semiconductors, cooperative and correlated interactions determine the material’s excitonic properties can even lead to creation of states matter. Here, we study fundamental two-particle exciton state formed by Coulomb interaction between single-particle holes electrons. We find that ultrafast transfer an exciton’s hole across a type II band-aligned semiconductor heterostructure leads unexpected sub-200-femtosecond upshift energy electron being photoemitted from state....