Berlin 2012 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 49: Nanomaterials II
MM 49.4: Talk
Thursday, March 29, 2012, 12:30–12:45, H 1029
Structural and electrical properties of silicon/silicon dioxide nanostructures grown by decomposition of SiOx for photovoltaic applications — •Maurizio Roczen1, Martin Schade2, Thomas Barthel1, Jan Amaru Töfflinger1, Abdelazize Laades3, Michael Blech3, Enno Malguth1, Hartmut Leipner2, Lars Korte1, and Bernd Rech1 — 1HZB, Institut für Silizium-Photovoltaik, Berlin, Germany — 2MLU, IZM, Halle, Germany — 3CiS, Erfurt, Germany
For the application as nanodot hetero-emitter the self organized growth of Si/SiO2 nanostructures by decomposition of sub-stoichiometric SiOx layers is investigated as well as the structural and electrical and properties of the nanodot system. The SiOx layers are deposited by PVD and CVD techniques onto crystalline Si (c-Si) wafers. The O/Si ratio is obtained by XPS and EDX measurements. XPS shows that decomposition of SiOx is completed after annealing the films at 900 °C. The growth of crystalline Si nanodots is shown in HRTEM images and confirmed by Raman spectroscopy. The size and density of the nanostructures is controlled by the applied annealing temperature and oxygen content. Oxygen rich films show a blue shifted photoluminescence signal which might be related to quantum size effects. Hydrogen concentration of CVD deposited SiOx decreases with increasing oxygen with direct influence on the charge carrier lifetime. The current density through the c-Si/SiOx system decreases with increasing oxygen content. AFM current mapping show a reduction of percolation paths. Doped SiOx induces a band bending of 730 meV in the substrate.