A5002617056- Advanced Thermoelectric Materials and Devices
- Anodic Oxide Films and Nanostructures
- Magnetic properties of thin films
- Semiconductor materials and devices
- Thermal properties of materials
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Topological Materials and Phenomena
- Nanowire Synthesis and Applications
- Nanoporous metals and alloys
- Electronic and Structural Properties of Oxides
- Thermal Radiation and Cooling Technologies
- ZnO doping and properties
- 2D Materials and Applications
- Quantum and electron transport phenomena
- Chalcogenide Semiconductor Thin Films
- Semiconductor materials and interfaces
- Shape Memory Alloy Transformations
- Heusler alloys: electronic and magnetic properties
- Graphene research and applications
- Ferroelectric and Piezoelectric Materials
- Magnetic Properties and Applications
- Multiferroics and related materials
- Photonic Crystals and Applications
- High Entropy Alloys Studies
Leibniz Institute for Solid State and Materials Research
2016-2025
Technische Universität Dresden
2016-2025
Complexity and Topology in Quantum Matter
2022
Shanghai University
2022
Universität Hamburg
2010-2019
Material (Belgium)
2018
Helmholtz-Zentrum Dresden-Rossendorf
2018
Tokyo University of Agriculture and Technology
2017
Nagoya University
2017
Southeast University
2017
Self-organized hexagonal pore arrays with a 50–420 nm interpore distance in anodic alumina have been obtained by anodizing aluminum oxalic, sulfuric, and phosphoric acid solutions. Hexagonally ordered distances as large 420 were under constant potential acid. By comparison of the formation three types electrolyte, it was found that show polycrystalline structure few micrometers size. The increases linearly potential, relationship from disordered porous also fits for periodic arrangements....
Transmission electron microscopy analysis of self-ordered porous alumina obtained by electrochemical anodization shows that self-ordering requires a porosity 10%, independent the specific conditions. This corresponds to volume expansion aluminum about 1.2. We propose with any interpore distance is possible if applied potential, which mainly determines distance, and pH value electrolyte, defines pore radius, match 10% rule.
Abstract Atomic layer deposition (ALD) has recently become the method of choice for semiconductor industry to conformally process extremely thin insulating layers (high‐ k oxides) onto large‐area silicon substrates. ALD is also a key technology surface modification complex nanostructured materials. After briefly introducing ALD, this Review will focus on various aspects nanomaterials and their processing by including nanopores, nanowires ‐tubes, nanopatterning nanolaminates as well...
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Ordered arrays of nickel nanowires have been prepared using pulsed electrodeposition. Two self-patterning anodization processes were used to fabricate alumina pore matrices into which was deposited from a Watts bath: two short millisecond deposition pulses followed by long delay yielded almost 100 % filled pores (see Figure). Nanowire are expected important applications as magnetic memories.
The magnetic behavior of 100 nm period arrays Ni nanowires embedded in a highly ordered alumina pore matrix were characterized by magnetometry and force microscopy. Reducing the diameter from 55 to 30 while keeping interwire distance constant leads increasing coercive fields 600 1200 Oe remanence 30% 100%. domain structure exhibits demagnetized state labyrith-like pattern. These results show that stray field interactions single are entirely dependent on nanowire diameter.
The Kirkendall effect has been widely applied for fabrication of nanoscale hollow structures, which involves an unbalanced counterdiffusion through a reaction interface. Conventional treatment this process only considers the bulk diffusion growth species and vacancies. In letter, conceptual extension is proposed: development interior undergoes two main stages. initial stage generation small voids intersecting compound interface via process; second dominated by surface core material (viz.,...
Highly ordered silver nanowire arrays have been obtained by pulsed electrodeposition in self-ordered porous alumina templates. Homogeneous filling of all the pores template is achieved. The interwire distance about 110 nm corresponding to a density nanowires 61×109 in.−2 and diameter can be varied between 30 70 nm. wires are monocrystalline with some twin lamella defects grow perpendicular 〈110〉 direction. previously encountered difficulty obtain 100% discussed framework electrostatic...
Abstract Thermoelectric materials are capable of converting waste heat into electricity. The dimensionless figure-of-merit (ZT), as the critical measure for material’s thermoelectric performance, plays a decisive role in energy conversion efficiency. Half-Heusler materials, one most promising candidates power generation, have relatively low ZTs compared to other material systems. Here we report discovery p -type ZrCoBi-based half-Heuslers with record-high ZT ∼1.42 at 973 K and high...
Discovery of thermoelectric materials has long been realized by the Edisonian trial and error approach. However, recent progress in theoretical calculations, including ability to predict structures unknown phases along with their thermodynamic stability functional properties, enabled so-called inverse design Compared traditional discovery, approach potential substantially reduce experimental efforts needed identify promising compounds target functionalities. By adopting this approach, here...
Copper sulfides and copper selenides have recently been reported as new promising low‐cost environmentally friendly thermoelectric materials. Here, it is shown that these materials actually studied for more than 190 years the absence of commercial modules based on them stems from some major intrinsic issues related to chalcogenides. Further development semiconductors will require addressing solving problems before large scale utilization can be considered.
High-quality single crystals of MnBi2Te4 are grown for the first time by slow cooling within a narrow range between melting points Bi2Te3 (586 °C) and (600 °C). Single-crystal X-ray diffraction electron microscopy reveal ubiquitous antisite defects in both cation sites and, possibly, Mn vacancies (Mn0.85(3)Bi2.10(3)Te4). Thermochemical studies complemented with high-temperature establish limited phase stability metastability at room temperature. Nevertheless, synthesis can be scaled-up as...
Abstract Thermoelectric materials could play an increasing role for the efficient use of energy resources and waste heat recovery in future. The thermoelectric efficiency is described by figure merit ZT = ( S 2 σT )/ κ Seebeck coefficient, σ electrical conductivity, thermal T absolute temperature). In recent years, several groups worldwide have been able to experimentally prove enhancement reduction conductivity due phonon blocking at nanostructured interfaces. This review addresses...
Abstract Thermoelectric technology converts heat into electricity directly and is a promising source of clean electricity. Commercial thermoelectric modules have relied on Bi 2 Te 3 -based compounds because their unparalleled properties at temperatures associated with low-grade (<550 K). However, the scarcity elemental greatly limits applicability such modules. Here we report performance assembled from -substitute compounds, including p-type MgAgSb n-type Mg (Sb,Bi) , by using simple,...
Thermoelectric interface materials (TEiMs) are essential to the development of thermoelectric generators. Common TEiMs use pure metals or binary alloys but have performance stability issues. Conventional selection generally relies on trial-and-error experimentation. We developed a TEiM screening strategy that is based phase diagram predictions by density functional theory calculations. By combining with electrical resistivity and melting points potential reaction products, we discovered...
Demonstration of a robust, tellurium-free thermoelectric module for near-room-temperature applications with high conversion efficiency 8.5% and maximum cooling 72 K.
Abstract Many thermoelectric materials benefit from complex microstructures. Grain boundaries (GBs) in nanocrystalline thermoelectrics cause desirable reduction the thermal conductivity by scattering phonons, but often lead to unwanted loss electrical charge carriers. Therefore, modifying GBs suppress their resistivity plays a pivotal role enhancement of performance, zT . In this work, different characteristics GB phases Ti‐doped NbFeSb half‐Heusler compounds are revealed using combination...
Hexagonally ordered nanopore arrays in anodic alumina with high aspect ratios (see Fig.) have been produced using a self-organization process. The pore are straight and parallel, of polycrystalline structure. distance between pores can be controlled by adjusting the electrolyte applied voltage. could find application as photonic crystals.
Bimetallic nanotubes: Uniform arrays of metal nanotubes were prepared by the electrodeposition a thin metallic film on pore walls anodic aluminum oxide membranes decorated with nanoparticles. Multisegmented bimetallic stacking configuration along nanotube axis can be fabricated (see picture). The technique is applicable to wide variety conducting and semiconducting materials. Supporting information for this article available WWW under...