Dresden 2011 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 43: Poster II: Thin Film Chalcogenide Photovoltaics; Thermoelectric Materials, Thin Films, and Nanostructures

DS 43.15: Poster

Mittwoch, 16. März 2011, 15:00–17:30, P2

Doping of hydrogenated a-Si and a-Ge nanostructures — •Christoph Grüner, Jens Bauer, Chinmay Khare, and Bernd Rauschenbach — Leibniz-Institut für Oberflächenmodifizierung, Permoserstrasse 15, D-04318 Leipzig, Germany

Nanostructured semiconductor thin films promise high performance in future thermoelectric applications. Glancing angle deposition (GLAD) is a recent technique to fabricate self-organized nanostructures. Based on shadowing at oblique incidence angle separated nanocolums evolve, which can be shaped by substrate rotation about its normal. As a result vertical nanospirals, nanoscrews, or nanocolumns are formed. By variing the incidence angle the deposition can be further customized. Amorphous hydrogenated silicon and germanium layers and nanostructures were grown by electron-beam evaporation at room temperature. Antimony and boron were used for in-situ doping by effusion cells. Hydrogenation is done with a hydrogen atom beam source. Hydrogen passivates the dangling bonds of the amorphous materials and thus it is used to enhance the electrical properties of doped a-Si and a-Ge films. We will present the influence of hydrogen on the dopant concentration and the electrical resistivity in a-Si and a-Ge thin films. The effect of Sb and B segregation will be discussed with respect to the hydrogen flux. The chemical composition is investigated by SIMS profiles. Furthermore, rapid temperature annealing experiments were performed for electrical activation of the dopants. Also the influence of hydrogenation and doping on the appearance and distribution of nanostructures is shown.