Dresden 2009 – scientific programme

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DS: Fachverband Dünne Schichten

DS 33: Thermoelectric Thin Films and Nanostructures I

DS 33.4: Talk

Thursday, March 26, 2009, 11:30–11:45, GER 38

Thermoelectric properties of thin films made from doped Si and Ge nanoparticles — •Konrad Schönleber¹, Robert Lechner¹, Roland Dietmüller¹, Martin S. Brandt¹, Hartmut Wiggers², and Martin Stutzmann¹ — ¹Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching — ²Institut für Verbrennungs- und Gasdynamik, Universität Duisburg-Essen, Lotharstraße 1, 47048 Duisburg

We investigate the applicability of doped Si and Ge nanoparticles for future thermoelectronic devices. The nanoparticles are prepared by plasma decomposition of silane or germane in a microwave reactor and have average sizes between 5 and 50 nm, depending on the preparation conditions. The particles can be doped n- or p-type by phosphorus or boron, respectively. Thin films are prepared by dissolving the particles in a suitable solvent such as ethanol, followed by spin coating. Kapton, silicon, or glass are used as substrates. The doping level and alloy composition of the particle films can be varied by mixing highly doped with undoped and Si with Ge particles, respectively As-deposited films are highly resistive, even at high doping levels and after removal of the native oxide shell surrounding the nanoparticles by HF treatment. In order to obtain sufficiently high conductivity levels for thermoelectric energy conversion, the films are treated with pulsed high energy laser. Electrical and thermal conductivities as well as Seebeck coefficients will be presented as a function of doping level, alloy composition, and laser treatment parameters.