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  • Dünne Schichten und Physik der Nanostrukturen

    *Pressemitteilung* ,,Mit winzigen Nanopartikeln zu besserem Ladungstransport (Nr. 75/2021)" Von Sepideh Izadi und Prof. Dr. Gabi Schierning Zur Pressemitteilung

    © Universität Bielefeld
    Mikrofluidkchip © Universität Bielefeld

Arbeitsgruppe Prof. Dr. Schierning


Über uns

Prof. Dr. Gabi Schierning

Fakultät Physik

Email
gschierning@physik.uni-bielefeld.de
Telefon
+49 521 106-2661
Telefon Sekretariat
+49 521 106-5412
Büro
UHG D2-114

Willkommen auf unserer Homepage der Arbeitsgruppe Schierning.

Forschungsschwerpunkte

  • Thermoelektrische Materialien und Bauelemente: Thermoelektrische Materialien wandeln Wärmeströme in elektrischen Strom und umgekehrt. Thermoelektrische Bauelemente können als Generatoren betrieben werden und in Kombination mit einer entsprechend auf niedrigen Verbrauch optimierten Elektronik Sensoren versorgen. Alternativ können diese Bauelemente sehr präzise und schnell Temperaturen einregeln, z.B. zur Temperaturstabilisierung von Lasern oder Laserdioden. Mikrobauelemente sind hierbei mit gängiger Halbleiterprozesstechnik kompatibel, so dass diese direkt an der entsprechenden elektronischen oder optischen Komponente platziert werden können.

 

  • Nanopartikel-basierte Quantenmaterialien: Nanopartikel zeichnen sich durch ihre große Oberfläche zu Volumenverhältnis aus. Topologische Isolatoren sind Quantenmaterialien mit besonderen, geschützten Transportkanälen an der Oberfläche. Die besten thermoelektrischen Materialien sind auch die bekanntesten topologischen Isolatoren. Durch ein Nanopartikel-basiertes Materialdesign ist es möglich, die Transporteigenschaften von topologischen Oberflächen bei relativ hohen Temperaturen an makroskopischen Proben zu untersuchen.

Themen für wissenschaftliche Arbeiten

Grundlagenorientierte Themen

  • Untersuchung (und dann Modifikation) von topologisch geschützten Oberflächen-Transportkanäle
  • Untersuchung der elektronischen Entropiebeiträge in Metallen nahe Phasenübergängen

Anwendungsnahe Themen

  • Thermoelektrische Mikrogeneratoren
  • Assemblierung von Prototypen
  • Ggfl. Studienabschlussarbeiten bei Industriepartnern

Aufbau Messtechnik

  • Hochtemperatur Hall Messplatz

Team

Prof. Dr. Gabi Schierning

Büro
D2-114
Email
gschierning@physik.uni-bielefeld.de

Sepideh Izadi

Doktorandin

Büro
D2-116
Email
sizadi@physik.uni-bielefeld.de

Lauritz Ule Schnatmann

Doktorand

Büro
D2-118
Email
lschnatmann@physik.uni-bielefeld.de
Telefon
+49 521 106-2585

Alexander Kunzmann

Doktorand

Büro
D2-118
Email
akunzmann@physik.uni-bielefeld.de
Telefon
+49 521 106-2585

Susanne Kunzmann

Doktorandin

Büro
D2-201
Email
skunzmann@physik.uni-bielefeld.de

Frederik Schulz

HiWi

Büro
D2-116
Email
fschulz@physik.uni-bielefeld.de

Niklas Libke

HiWi

Büro
D2-116
Email
nlibke@uni-bielefeld.de

Timon Sieweke

Masterstudent

Büro
D2-118
Email
tsieweke@physik.uni-bielefeld.de
Telefon
+49 521 106-2585

Michelle Nikolova

HiWi

Büro
D2-116
Email
mnikolova@physik.uni-bielefeld.de

Projekte


- ERC

Source: https://erc.europa.eu/managing-your-project/communicating-your-research
Source: https://europa.eu/european-union/about-eu/symbols/flag_en

MAcroscopic quantum Transport maTERials by nanoparticle processing (MATTER)

ERC Consolidator Grant 2019

Funding period: 01.06.2020-31.05.2025

 

Abstract

Ever since the discovery of topological surface states in three-dimensional (3D) topological insulators (TI), this fascinating physics has thrilled scientists. While arguable the transport properties of 3D TIs are of utmost importance for potential applications, they are extremely difficult to characterize, yet utilize for devices. The reason is that transport in those materials is always dominated by bulk carriers. Within this proposed research project, I will overcome the problem of bulk carrier domination conceptually by a nanoparticle-based materials’ design of interrupted early stage sintering. By this interrupted early stage sintering approach, I compact 3D TI nanoparticles at mild temperature and low pressure. The obtained highly porous macroscopic sample features a carrier density of the surface states in the order of 1018 cm-3, hence in a comparable order of magnitude as the bulk carrier density. Further, the interruptedly sintered nanoparticles impose energetic barriers for the transport of bulk carriers (hopping transport), while the connected surfaces of the nanoparticles provide a 3D percolation path for surface carriers. Within the preliminary work, my group tuned interruptedly sintered nanoparticles into a transport regime completely dominated by the surface states.

Within this project, nanoparticle-based macroscopic 3D TI materials will be developed towards test structures for devices. Their properties will be tailored by the nanoparticle synthesis (Objective 1) and the materials processing of interrupted early stage sintering (Objective 2). This is complemented by an in-depth characterization of the transport as well as spectroscopic properties and data modelling (Objective 3). My group will use this know-how for the fabrication of test devices (Objective 4). This combination will provide the first macroscopic quantum transport devices that utilize the unique electronic properties of surface states, overcoming the problem of bulk carrier domination.

 

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme. Grant agreement No. 863823.

 

 

 


The unique appraoch:

A particle based materials design concept

Key benefits of compacted nanoparticle arrays

 

  •    High surface-to-volume ratio
  •    Energy barriers between grains
  •    3D percolation network for surface carriers

 

Exciting evidence of surface conductance

  • Unique transport channel
  • Change of slope / sign in Hall-experiments
  • Weak antilocalisation

Research strategy and objectives

OBJECTIVE 1 SYNTHESIZING

 

  • Highly stoichiometric nanoparticles
  • Free of contamination
  • Scalable approach
     

OBJECTIVE 2 PROCESSING

 

  • Compaction by interrupted early stage sintering
  • Contacting
     

OBJECTIVE 3 CHARACTERIZING

 

  • Low temperature magneto and thermoelectric transport
  • Data modelling
     

OBJECTIVE 4 DEVELOPING DEVICES

 

  • Proof-of-principle test structures
  • Gating
  • Magnetic device structures
     

- DFG

Thermo-Harvested Autarkic Wireless Integrated Transmitter THAWIT

For the internet of things (IoT) in general and medical sensors in particular, low power wireless data transmitters are required. Up to date, most of such transmitters require batteries or inefficient radio frequency (RF) harvesting.

In THAWIT, we want to investigate and demonstrate the first wireless data transmitter, which can be supplied by means of compact integrated thermoelectric harvesting. To allow supply-autarkic operation, we have to meet the following challenges. The power consumption of the transmitter must be massively reduced. Moreover, the power density of the thermoelectric devices must be increased. A major challenge is the capability for integration on silicon limiting the possible material compositions. We want to develop silicon-compatible harvesting elements with a power density beyond 10 μW/mm2 at a moderate temperature difference of 7 K. To meet this challenge, we rigorously optimise the geometry and material compositions. A high thermoelectric leg height is necessary for high output power density, affecting the choice of the photoresist and deposition parameters of the thermoelectric material. A new process for the p-type thermoelectric leg is researched to reduce the thermal conductivity. In addition, we develop a silicon-compatible micro-supercapacitor serving as energy buffer. To enable compatibility with the fabrication technology and equipment at IFW, we realize it by a high-performance all-solid-state interdigital in-plane micro-supercapacitor. It is based on photo-lithographically patterned sputtered electrodes and a solid electrolyte.

Considering energy saving losses and component areas of 2 mm2, the CMOS transmitter must operate with a dc power of around 10 μW. To enable such an ultra-low dc power, we study direct modulated oscillators with aggressive duty-cycling of around 0.1 %, fast ramp-up and miniaturized leakage in the sleep phases. In addition to impedance-matched antennas requiring buffer amplifiers, we consider also inductive antennas which can be directly incorporated in the LC-resonator of the oscillator. A textile-compatible woven or printed antenna is designed for the demonstrator. The demonstrator shall operate according to the medical implant communication service (MICS). The final goal is to show data transmission around 400 MHz with a data rate of 1-10 kb/s for distances of up to 1 meter. THAWIT combines the complementary competences of Gabi Schierning, IFW, in the area of thermoelectric devices, and Frank Ellinger, TUD regarding low power integrated RF circuits.

 

This project has received funding from the Deutsche Forschungsgemeinschaft (DFG) under grand number SCHI 1010/12-1.


Publikationen und Pressemitteilungen

Publikationen

Die komplette Puplikationsliste finden Sie hier.

 

  • 2021 | Zeitschriftenaufsatz | Veröffentlicht | PUB-ID: 2952479

Towards tellurium-free thermoelectric modules for power generation from low-grade heat.
Ying P, He R, Mao J, Zhang Q, Reith H, Sui J, Ren Z, Nielsch K, Schierning G (2021)
Nature communications 12(1): 1121

Abstract

"Thermoelectric technology converts heat into electricity directly and is a promising source of clean electricity. Commercial thermoelectric modules have relied on Bi2Te3-based compounds because of their unparalleled thermoelectric properties at temperatures associated with low-grade heat (<550 K). However, the scarcity of elemental Te greatly limits the applicability of such modules. Here we report the performance of thermoelectric modules assembled from Bi2Te3-substitute compounds, including p-type MgAgSb and n-type Mg3(Sb,Bi)2, by using a simple, versatile, and thus scalable processing routine. For a temperature difference of ~250 K, whereas a single-stage module displayed a conversion efficiency of ~6.5%, a module using segmented n-type legs displayed a record efficiency of ~7.0% that is comparable to the state-of-the-art Bi2Te3-based thermoelectric modules. Our work demonstrates the feasibility and scalability of high-performance thermoelectric modules based on sustainable elements for recovering low-grade heat."


  • 2021 | Zeitschriftenaufsatz | Veröffentlicht | PUB-ID: 2951299

Influence of Nanoparticle Processing on the Thermoelectric Properties of (BixSb1-X)(2)Te-3 Ternary Alloys
Salloum S, Bendt G, Heidelmann M, Loza K, Bayesteh S, Sepideh Izadi M, Kawulok P, He R, Schlorb H, Perez N, Reith H, et al. (2021)
ChemistryOpen 10(2): 189-198.

Abstract

“The synthesis of phase-pure ternary solutions of tetradymite-type materials (BixSb1-x)(2)Te-3 (x=0.25; 0.50; 0.75) in an ionic liquid approach has been carried out. The nanoparticles are characterized by means of energy-dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and transmission electron microscopy. In addition, the role of different processing approaches on the thermoelectric properties - Seebeck coefficient as well as electrical and thermal conductivity - is demonstrated.“

 


Curriculum Vitae

Academic Education with Degree

Date Field University Degree
2002 Material Science and Engineering University of Erlangen-Nürnberg Dipl. Ing.
2005 Material Science and Engineering University of Erlangen-Nürnberg Dr.Ing.
2016 Materials for Electrical Engineering University of Duisburg-Essen Dr. Ing. habil.

Professional career

Since 2020

W2 TT W3 Professor for experimental physics, department of physics, University of Bielefeld, Germany

2015-2020

Head of group „Thermoelectric materials and devices“, in the Institute for Metallic Materials, Leibniz-Institute for solid state and materials science Dresden e.V. (IFW-Dresden), Germany, with director Prof. K. Nielsch

2009-2015

Leader of an independent young researcher group in the department of electrical engineering, University of Duisburg-Essen, Germany

2007-2015

Research assistant in the department of electrical engineering, University of Duisburg-Essen, Germany, with Prof. R. Schmechel

2005-2007

Research assistant in the Institute for Nanotechnology, Karlsruhe Institute of Technology (KIT), Germany, with director Prof. H. Hahn

2005 Employee at Siemens Medical Solutions, Forchheim
2005

Research assistant in the department of materials science, Darmstadt Technical University, Germany, with Prof. H. von Seggern

2005

Research internship in the school of chemical and physical sciences, Victoria University of Wellington, New Zealand, with Prof. A. Edgar

2002-2004

Research assistant in the department of materials science and engineering, University of Erlangen-Nürnberg, Germany, with Prof. A. Winnacker


Distinctins and awards

  • ERC Consolidator Grant, 2019
  • Award of innovation of the State of North-Rhine Westphalia in the category “Young Researcher” (Germany), 2014
  • Innomateria Award, 2012
  • Nomination for the ars legendi award of faculties by the student body of NanoEngineering (University of Duisburg-Essen, Germany), 2011
  • Young Researcher Group, awarded by the State of North-Rhine Westphalia (Germany), 2009
  • Award of excellence by the Ministry of Science, Research and Arts of the State of Bavaria for the diploma thesis, 2003

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