René Hübner's research while affiliated with Helmholtz-Zentrum Dresden-Rossendorf and other places

Publications (262)

Article
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Robust spin injection and detection in antiferromagnetic thin films is a prerequisite for the exploration of antiferromagnetic spin dynamics and the development of nanoscale antiferromagnet-based spintronic applications. Previous studies have shown spin injection and detection in antiferromagnet/nonmagnetic metal bilayers; however, spin injection i...
Article
Europium, as an easy-to-study analog of the trivalent actinides, is of particular importance for studying the behavior of lanthanides and actinides in the environment. Since different soil organisms can influence the migration behavior of these elements, a detailed knowledge of these interaction mechanisms is important. The aim of this study was to...
Article
Binary magnetic alloys like Co-Pt are relevant for applications as components of magnetic exchange coupled composites. Numerous approaches exist to tune the coercive field of Co-Pt alloys primarily relying on high temperature processing aiming to realize chemically long-range ordered phases. The peculiarity of Co-Pt is that large coercive field and...
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The combination of plasmonic nanoparticles and optical microcavities has attracted broad interest for both fundamental and applied studies. However, the conventional scheme of plasmonic nanoparticles being located at microcavity outer surfaces suffers from serious problems such as significant radiative/scattering losses and chemical/mechanical inst...
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Daucus carota suspension cells showed a high affinity towards Eu(III) and U(VI) based on a single-step bioassociation process with an equilibrium after 48 to 72 h. Cells responded with an increased metabolic activity towards heavy metal stress. Luminescence spectroscopy pointed to multiple species for both f-block elements in the culture media, pro...
Preprint
Cadmium chalcogenide nanoplatelets (NPLs) are established as promising materials for a wide variety of optoelectronic applications due to their properties surpassing in many aspects counterpart nanocrystals (NCs) with other shapes. Most of these features arise from strong quantum confinement in the direction of thickness which can be tuned with pre...
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The natural bacterial spores have inspired the development of artificial spores, through coating cells with protective materials, for durable whole-cell catalysis. Despite attractiveness, artificial spores developed to date are generally limited to a few microorganisms with their natural endogenous enzymes, and they have never been explored as a ge...
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The oxygen evolution reaction is central to making chemicals and energy carriers using electrons. Combining the great tunability of enzymatic systems with known oxide-based catalysts can create breakthrough opportunities to achieve both high activity and stability. Here we report a series of metal hydroxide–organic frameworks (MHOFs) synthesized by...
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The U(VI) bioassociation on Magnetospirillum magneticum AMB-1 cells was investigated using a multidisciplinary approach combining wet chemistry, microscopy, and spectroscopy methods to provide deeper insight into the interaction of U(VI) with bioligands of Gram-negative bacteria for a better molecular understanding. Our findings suggest that the ce...
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Due to their self-supporting and nanoparticulate structure, metal aerogels have emerged as excellent electrocatalysts, especially in the light of the shift to renewable energy cycles. While a large number of synthesis parameters have already been studied in depth, only superficial attention has been paid to the solvent. In order to investigate the...
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Silicon oxide films are widely applied for their superior dielectric, chemical and mechanic properties as well as for their resistance against reactive chemicals. Simultaneously, there is an increasing number of applications which demand a low deposition temperature. In this work, we compare the material properties of SiOx layers deposited on silic...
Article
Thin films of the magnetoelectric insulator α‐Cr2O3 are technologically relevant for energy‐efficient magnetic memory devices controlled by electric fields. In contrast to single crystals, the quality of thin Cr2O3 films is usually compromised by the presence of point defects and their agglomerations at grain boundaries, putting into question their...
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Plasmonic sensing in the infrared region employs the direct interaction of the vibrational fingerprints of molecules with the plasmonic resonances, creating surface-enhanced sensing platforms that are superior to traditional spectroscopy. However, the standard noble metals used for plasmonic resonances suffer from high radiative losses as well as f...
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Endocytosis of metals in plants is a growing field of study involving metal uptake from the rhizosphere. Uranium, which is naturally and artificially released into the rhizosphere, is known to be taken up by certain species of plant, such as Nicotiana tabacum, and we hypothesize that endocytosis contributes to the uptake of uranium in tobacco. The...
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The important role of structure homogeneity in three-dimensional network nanostructures such as noble metal aerogels (NMAs) has attracted wide spread attention in the field of electrochemistry in the last two...
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The proline-catalyzed aldol reactions have been developed as an important toolbox for the synthesis of valuable chiral intermediates, giving birth to asymmetric organocatalysis. Despite progress, their concurrent applications are generally...
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The remediation of heavy-metal-contaminated sites represents a serious environmental problem worldwide. Currently, cost- and time-intensive chemical treatments are usually performed. Bioremediation by heavy-metal-tolerant microorganisms is considered a more eco-friendly and comparatively cheap alternative. The fungus Penicillium simplicissimum KS1,...
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The dynamics of the pattern induced on a silicon surface by oblique incidence of a 40 keV Fe ion beam is studied. The results are compared with those obtained for two reference systems namely, a noble gas ion beam either without or with Fe co-deposition. The techniques employed include Atomic Force Microscopy, Rutherford Backscattering Spectrometry...
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Transistor concepts based on semiconductor nanowires promise high performance, lower energy consumption and better integrability in various platforms in nanoscale dimensions. Concerning the intrinsic transport properties of electrons in nanowires, relatively high mobility values that approach those in bulk crystals have been obtained only in core/s...
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Clay formations are potential host rocks for the long-term storage of high-level radioactive waste in a deep geological repository. Bentonites are supposed to serve as backfill material, not only for a final disposal site in clay formations but also in crystalline rock. For a long-term safety assessment, various aspects must be taken into account....
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The fabrication of individual nanowire-based devices and their comprehensive electrical characterization remains a major challenge. Here, we present a symmetric Hall bar configuration for highly p-type germanium nanowires (GeNWs), fabricated by a top-down approach using electron beam lithography and inductively coupled plasma reactive ion etching....
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InGaN/GaN quantum wells (QWs) with sub-nanometer thickness can be employed in short-period superlattices for bandgap engineering of efficient optoelectronic devices, as well as for exploiting topological insulator behavior in III-nitride semiconductors. However, it had been argued that the highest indium content in such ultra-thin QWs is kineticall...
Preprint
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The efficient integration of transition metal dichalcogenides (TMDs) into the current electronic device technology requires mastering the techniques of effective tuning of their optoelectronic properties. Specifically, controllable doping is essential. For conventional bulk semiconductors, ion implantation is the most developed method offering stab...
Preprint
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Magnetic skyrmions have been suggested as information carriers for future spintronic devices. As the first material with experimentally confirmed skyrmions, B20-type MnSi was the research focus for decades. Although B20-MnSi films have been successfully grown on Si(111) substrates, there is no report about B20-MnSi films on Si(100) substrates, whic...
Article
The effects of hydrogen absorption on the effective magnetization (4πMeff), gyromagnetic ratio (γ), Gilbert damping constant (αG), and the inhomogeneous linewidth broadening (ΔH0) in Py(x)/Y(16 nm)/Pd(15 nm) trilayer films (x=2, 3, 5, 8, 10, 20, 40 nm) were investigated with ferromagnetic resonance (FMR), transmission electron microscopy, and vibra...
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Full-text available
Magnetic skyrmions have been suggested as information carriers for future spintronic devices. As the first material with experimentally confirmed skyrmions, B20-type MnSi was the research focus for decades. Although B20-MnSi films have been successfully grown on Si(111) substrates, there is no report about B20-MnSi films on Si(100) substrates, whic...
Article
Self‐supported gold aerogels of centimeter‐dimension and tunable ligament sizes are designed by Ran Du, Yue Hu, Alexander Eychmüller and co‐workers (article number 2100352) as new‐type 3D surface‐enhanced Raman scattering (SERS) substrates, featuring abundant hot spots distributed in 3D space. By investigating the ligament‐size‐effect on SERS perfo...
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Lateral-channel dual-gate organic thin-film transistors have been used in pseudo complementary metal–oxide–semiconductor (CMOS) inverters to control switching voltage. However, their relatively long channel lengths, combined with the low charge carrier mobility of organic semiconductors, typically leads to slow inverter operation. Vertical-channel...
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Designing cost-effective, highly active, and durable platinum (Pt)-based electrocatalysts is a crucial endeavor in electrochemical hydrogen evolution reaction (HER). Herein, the low-content Pt (0.8 wt%)/tungsten oxide/reduced graphene oxide aerogel (LPWGA) electrocatalyst with excellent HER activity and durability is developed by employing a tungst...
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The formation of nanopores by highly charged ion impacts on freestanding fluorine-functionalized graphene is demonstrated. The process is driven by potential sputtering, which becomes active by changing the semimetallic property of graphene into a strongly insulating state by fluorination. The interaction of fluorographene with highly charged ions...
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CuCr2O4 thin films grown by physical vapour deposition were studied in order to evaluate their potential as absorber material for the next generation of concentrated solar power plants. A series of Cu-Cr-O thin films was deposited by reactive ion beam sputtering. The Cr/Cu ratio in the sputter target is demonstrated as the most important parameter...
Article
Si hyperdoped with chalcogens via ion implantation and pulsed laser melting is known to exhibit strong room-temperature sub-bandgap photoresponse. As a thermodynamically metastable system, an impairment of the optoelectronic properties in hyperdoped Si materials occurs upon subsequent high-temperature thermal treatment (> 500 °C). The substitutiona...
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Organic light-emitting transistors, three-terminal devices combining a thin-film transistor with a light-emitting diode, have generated increasing interest in organic electronics. However, increasing their efficiency while keeping the operating voltage low still remains a key challenge. Here, we demonstrate organic permeable base light-emitting tra...
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The research on surface-enhanced Raman scattering (SERS) continuously draws wide attention because of its high detection sensitivity. However, the commonly investigated 2D SERS substrates cannot fully utilize the 3D active focal volume and require a tight focus on the correct plane, retarding signal enhancement and flexible use. Here, self-supporte...
Article
Cation exchange emerged as a versatile tool to obtain a variety of nanocrystals not yet available via a direct synthesis. Reduced reaction times and moderate temperatures make the method compatible with anisotropic nanoplatelets (NPLs). However, the subtle thermodynamic and kinetic factors governing the exchange require careful control over the rea...
Article
In this study, we investigated the interaction of U(VI) and Eu(III) with Brassica napus suspension plant cells as a model system. Concentration-dependent (0-200 μM) bioassociation experiments showed that more than 75% of U(VI) and Eu(III) were immobilized by the cells. In addition to this phenomenon, time-dependent studies for 1 to 72 h of exposure...
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B20‐type transition‐metal silicides or germanides are noncentrosymmetric materials hosting magnetic skyrmions, which are promising information carriers in spintronic devices. The prerequisite is to prepare thin films on technology‐relevant substrates with magnetic skyrmions stabilized at a broad temperature and magnetic‐field working window. A cano...
Article
In the present work, we have studied the influence of gold nanoparticles (AuNPs) on the photoluminescence (PL) behavior of cadmium selenide (CdSe) quantum dots (QDs) confined in spatially separated soft nanoscale cylindrical domains. These cylindrical domains, in the form of hairy core‐shell nanofibers, were fabricated via cooperative self‐assembly...
Article
The efficient integration of transition metal dichalcogenides (TMDs) into the current electronic device technology requires mastering the techniques of effective tuning of their optoelectronic properties. Specifically, controllable doping is essential. For conventional bulk semiconductors, ion implantation is the most developed method offering stab...
Article
B20-type FeGe is one of the noncentrosymmetric materials hosting magnetic skymions. In this work, we have prepared B20-type FeGe films by pulsed laser melting of metal Fe deposited on Ge(100). The formation of the B20 phase is confirmed by X-ray diffraction. The FeGe samples show a superparamagnetic behaviour and their blocking temperatures increas...
Preprint
Full-text available
Highly crystalline UO2 nanoparticles (NPs) with sizes of 2-3 nm were produced by fast chemical deposition of uranium(IV) under reducing conditions at pH 8-11. The particles were then characterized by microscopic and spectroscopic techniques including high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), high-energy reso...
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Terrestrial accelerator facilities can generate ion beams which enable the testing of the resistance of materials and thin flm coatings to be used in the space environment. In this work, a TiO2/Al bi-layer coating has been irradiated with a He+ beam at three diferent energies. The same fux and dose have been used in order to investigate the damage...
Article
Insufficient catalytic activity and stability, and high cost are the key barriers for Pt‐based electrocatalysts in wide practical applications. Herein, a hierarchically porous PtNi nanoframe/N‐doped graphene aerogel (PtNiNF‐NGA) electrocatalyst with outstanding performance toward methanol oxidation reaction (MOR) in acid electrolyte has been develo...
Article
PtNiNF‐NGA has PtNi nanoframes (PtNiNFs) with a high alloying degree, Pt‐rich corners and thin edges, anchoring effect of the N‐doped graphene aerogel to the PtNiNF, and hierarchical porosity. This endows it with fast mass transfer, enhanced intrinsic structure stability, modulated electronic state and optimized methanol oxidation reaction pathway,...
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We have studied thermally driven magnon spin transport (spin Seebeck effect, SSE) in heterostructures of antiferromagnetic α-Cr2O3 and Pt at low temperatures. Monitoring the amplitude of the local and nonlocal SSE signals as a function of temperature, we found that both decrease with increasing temperature and disappear above 100 K and 20 K, respec...
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This paper reports on the development of tumor-specific gold nanoparticles (AuNPs) as theranostic tools intended for target accumulation and the detection of tumor angiogenesis via optical imaging (OI) before therapy is performed, being initiated via an external X-ray irradiation source. The AuNPs were decorated with a near-infrared dye, and RGD pe...
Article
After the Chernobyl and Fukushima incidents it has become clear that fungi can take up and accumulate large quantities of radionuclides and heavy metals, but the underlying processes are not well understood yet. For this study, the molecular interactions of uranium(VI) with the white-rot fungi, Schizophyllum commune and Pleurotus ostreatus, and the...
Article
Armed with merits of the metals (e.g., electrical conductivity, catalytic activity, and plasmonic properties) and aerogels (e.g., monolithic structure, porous network, and large specific surface area), metal aerogels (MAs) have stood out as a new class of porous materials in the last decade. With unparalleled potential in electrocatalysis, plasmoni...
Article
We report a synthesis route to two-dimensional PbSe, HgSe, ZnSe, SnSe, and Cu–Zn–Sn–Se (CZTSe) nanomaterials based on cation exchange (CE) reactions. This approach includes two steps: it starts with the...
Article
Highly crystalline UO2 nanoparticles (NPs) with sizes of 2-3 nm were produced by fast chemical deposition of uranium(IV) under reducing conditions at pH 8-11. The particles were then characterized by microscopic and spectroscopic techniques including high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), high-energy reso...
Article
Full-text available
The n-type doping of Ge is a self-limiting process due to the formation of vacancy-donor complexes (D n V with n ⩽ 4) that deactivate the donors. This work unambiguously demonstrates that the dissolution of the dominating P4V clusters in heavily phosphorus-doped Ge epilayers can be achieved by millisecond-flash lamp annealing at about 1050 K. The P...