Regensburg 2004 – scientific programme

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HL: Halbleiterphysik

HL 44: Poster II

HL 44.19: Poster

Thursday, March 11, 2004, 16:30–19:00, Poster A

Anisotropic Thermopower in Si-Al-Multilayers — •Amir Kyarad und Hans Lengfellner — Institut für Angewandte und Experimentelle Physik, Universität Regensburg, 93040 Regensburg, Germany

Semiconductor-metal multilayer structures A-B-A... show, according to model calculations, large anisotropy in their electrical and thermal transport properties: For n-type silicon (A) and aluminum (B), the anisotropy of the thermopower Δ S = S_∥− S_⊥ where S_∥ and S_⊥ represent the Seebeck coefficients along and perpendicular to the layers, is more than an order of magnitude larger than that for a pure metallic structure A-B-A... made of constantan (A) and copper (B). In samples prepared with a tilt angle between sample surface and layer planes, radiation heating of the sample surface induces a surface perpendicular temperature gradient and, due to the anisotropy of the thermopower, generates a surface parallel thermoelectric field E ∼ Δ S. This transverse Seebeck effect suggests applications for radiation detection. The preparation of Si-Al multilayer samples is described and their use as rugged, self-powered and nearly wavelength independent detectors for laser radiation is demonstrated.