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DS: Fachverband Dünne Schichten
DS 42: Thermoelectric materials IV: Glass, sintered materials (Focused session – Organizers: Meyer, Heiliger)
DS 42.4: Vortrag
Freitag, 30. März 2012, 12:30–12:45, H 2032
Nanocrystalline Diamond as Thermoelectric Material — •Nicolas Wöhrl1, Markus Engenhorst2, Gabi Schierning2, and Volker Buck1 — 1University Duisburg-Essen and CeNIDE, Faculty of Physics, Duisburg, Germany — 2University Duisburg-Essen and CeNIDE, Faculty of Engineering, Duisburg, Germany
The thermoelectric effect directly converts temperature differences into electric voltage and vice versa. The thermoelectric material has to have a high electrical conductivity because a high internal resistance will reduce the efficiency of the generator and a low thermal conductivity. Thus one promising way to design good thermoelectric materials is to manipulate phonons and electrons at the nanoscale making nanostructuring a possible way to achieve these materials. Introducing defects that scatter phonons but not electrons at the same degree can decrease the thermal conductivity without appreciably affecting the power factor. Another strategy is to scatter phonons at interfaces, leading to the use of nanostructured materials consisting of thin-film superlattices or mixed composite structures. Nanocrystalline diamond films were deposited by microwave-plasma CVD from an Ar/H2/CH4 plasma with admixtures of trialkylborane to obtain p-type semiconducting diamond and results shown here are indicating that nanostructured diamond films are a promising material for thermoelectric applications. Thermal conductivity lower than 10 W/mK and Seebeck coefficients above 50 μV/K were achieved.