Thermoelectric Bi2Te3 Nanomaterials

Edited by the initiators of a priority research program funded by the German Science Foundation and written by an international team of key players, this is the first book to provide an overview of nanostructured thermoelectric materials -- putting the new developments into perspective alongside conventional thermoelectrics. As such, it reviews the current state of research on thermoelectric Bi2Te3 nanomaterials, covering advanced methods of materials synthesis, characterization of materials structures and thermoelectric properties, as well as advances in the theory and modeling of transport properties. Nanomaterials-based thermoelectric devices are also discussed with respect to their properties, their suitability for different energy generation applications, and in light of their commercialization potential. An outlook on the chances, challenges and future directions of research rounds off the book, giving a straightforward account of the fundamental and technical problems - plus ways to overcome them.

Autorentext
Kornelius Nielsch is Professor for Experimental Physics at the Institute of Applied Physics of the University Hamburg, Germany, and coordinator of the German Priority Program of Thermoelectric Nanostructures, funded by the German Science Foundation (DFG). After his PhD obtained for a doctoral thesis carried out at Max Planck Institute of Microstructure Physics in Halle, Germany, he was postdoctoral associate at MIT, USA. From October 2003 to December 2008 he was leader of the a nanotechnology research group funded by the German Federal Ministry of Education and Research (BMBF) on Multifunctional Nanowires and Nanotubes at the Max Planck Institute in Halle. He received the State Research Prize for Basic Research from the State of Saxony-Anhalt in 2006. In the same year he was appointed Full Professor for Experimental Physics in Hamburg.

Friedemann Volklein is Director of the Institute for Microtechnologies (IMtech) and Professor for Physical Technologies and Microsystem Technology at the RheinMain University of Applied Sciences in Wiesbaden. He received both his PhD and DSc degrees in Physics from the University of Jena, Germany. He specializes in solid-state physics of thin films and their applications in thermoelectric microsensors and microactuators. Before his move to Wiesbaden, he was head of the sensor department of the Institute for Photonic Technology (IPHT) Jena and senior scientist in the Physical Electronics Laboratory of the ETH Zurich, Switzerland.

Oliver Eibl is Professor for Applied Physics at the University of Tuebingen. He spent fifteen years as researcher at Siemens Corporate Research in Munich and started his university career in Tubingen in 1999. His field of research is electron microscopy and applied materials science. He is author of more than 100 scientific papers and holds more than ten patents. He has reviewed numerous scientific papers and has acted as a referee for numerous scientific research proposals.

Nicola Peranio is Research Scientist in Professor Eibl's group at the University of Tubingen. He received his Master degree from Karlsruhe Institute of Technology and his PhD from the University of Tubingen in 2008. In 2009 he obtained the Young Investigator Award from the German Thermoelectric Society (DTG) for his PhD thesis on Bi2Te3 bulk and nanomaterials.

Inhalt

Preface XIII

List of Contributors XVII

Acknowledgments XXIII

1 Old and New Things in Thermoelectricity 1
Rudolf P. Huebener

1.1 ThreeThermoelectric Effects 2

1.1.1 Seebeck Effect 2

1.1.2 Peltier Effect 3

1.1.3 Thomson Effect 3

1.2 Semiconductors 4

1.3 My Entry into Thermoelectricity 6

1.4 Peltier Cascades 9

1.5 Challenge of Materials Science 9

References 10

Part I: Synthesis of Nanowires, Thin Films, and Nanostructured Bulk 11

2 Electrodeposition of Bi2Te3-Based Thin Films and Nanowires 13
William Töllner, Svenja Bäßler, Nicola Peranio, Eckhard Pippel, Oliver Eibl, and Kornelius Nielsch

2.1 Introduction 13

2.2 Fundamentals of Bi2Te3-Based Electrodeposition 14

2.3 Electrodeposition of Bi2Te3 Thin Films 16

2.4 Electrodeposition of Thermoelectric Nanowires 21

2.4.1 Electrodeposition of Bi2Te3 Nanowires 21

2.4.2 Ternary Bi2Te3-Based Nanowires 28

2.5 Conclusion 31

References 31

3 Bi2Te3 Nanowires by Electrodeposition in Polymeric Etched Ion Track Membranes: Synthesis and Characterization 33
Oliver Picht, Janina Krieg, and Maria Eugenia Toimil-Molares

3.1 Introduction 33

3.2 Synthesis of Bi2Te3 NWs with Controlled Size and Crystallography 36

3.2.1 Fabrication of Etched Ion-Track Membranes 36

3.2.1.1 Swift Heavy-Ion Irradiation 36

3.2.1.2 Chemical Etching 37

3.2.2 Electrodeposition of Bi2Te3 NWs 38

3.2.2.1 Experimental Setup 38

3.2.2.2 Electrodeposition of Bi2Te3 and Choice of the Electrolyte 40

3.2.2.3 Chronoamperometric CurrentTime Curves 41

3.2.3 Morphological and Crystallographic Characterization of Bi2Te3 NWs 42

3.2.3.1 NWArrays 42

3.2.3.2 Morphology of Individual Nanowires as a Function of the Deposition Parameters 43

3.2.3.3 Adjusting the Nanowire Dimensions 44

3.2.3.4 Investigation of the Nanowire Crystallinity and Composition by TEM 45

3.2.3.5 Investigation of the Preferred Crystallographic Orientation of Wire Arrays by X-Ray Diffraction 49

3.3 Conclusions 50

References 51

4 Fabrication and Comprehensive Structural and Transport Property Characterization of Nanoalloyed Nanostructured V2VI3 Thin Film Materials 55
MarkusWinkler, Torben Dankwort, Ulrich Schürmann, Xi Liu, Jan D. König, Lorenz Kienle,Wolfgang Bensch, Harald Böttner, and Kilian Bartholomé

4.1 Situation/State of the Art before the Start of Our Combined Research Project 55

4.2 Motivation for Research on V2VI3 Multilayered Structures 56

4.2.1 BinaryThin Films 58

4.2.2 Results Obtained for SL Structures 62

4.2.3 Results Obtained from aTheoretical Analysis of V2VI3 Binaries and Nanoscale SL Structures 66

4.3 Conclusion and Outlook 67

Acknowledgments 69

References 69

5 Structure and Transport Properties of Bi2Te3 Films 73
GuoyuWang, Lynn Endicott, and Ctirad Uher

5.1 Introduction 73

5.2 Structural Aspects of the Tetradymite-type Lattice 75

5.3 MBE Film Deposition 76

5.4 Structural Characterization of Bi2Te3 Films 78

5.5 Transport Properties of Films on Sapphire Substrates 85

5.6 Conclusion 95

Acknowledgment 95

References 95

6 Bulk-Nanostructured Bi2Te3-Based Materials: Processing, Thermoelectric Properties, and Challenges 99
Vicente Pacheco, Henrik Görlitz, Nicola Peranio, Zainul Aabdin, and Oliver Eibl

6.1 Success of ZT Enhancement in Nanostructured Bulk Materials 99

6.2 Methodology at Fraunhofer IFAM-DD: Previous Research 100

6.3 High-Energy Ball Milling Technology, SPS Technology, and Thermoelectric Characterization 102

6.4 Control of Crystallite Size and Mass Density 103

6.4.1 Optimizing Ball Milling Parameters 103 <p&gt...