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DS: Fachverband Dünne Schichten
DS 42: Poster I: Progress in Micro- and Nanopatterning: Techniques and Applications (jointly with O); Spins in Organic Materials; Ion Interactions with Nano Scale Materials; Organic Electronics and Photovoltaics; Plasmonics and Nanophotonics (jointly with HL and O); High-k and Low-k Dielectrics (jointly with DF); Organic Thin Films; Nanoengineered Thin Films; Layer Deposition Processes; Layer Properties: Electrical, Optical, and Mechanical Properties; Thin Film Characterisation: Structure Analysis and Composition; Application of Thin Films
DS 42.74: Poster
Wednesday, March 16, 2011, 15:00–17:30, P1
Spectroscopic Investigations of DC Magnetron Sputtered Amorphous Silicon Thin Films — •Philipp Schäfer1, Frank Nobis2, Markus Arnold1, Ovidiu D. Gordan1, Hartmut Kupfer2, Frank Richter2, and Dietrich R. T. Zahn1 — 1Semiconductor Physics, Chemnitz University of Technology — 2Solid State Physics, Chemnitz University of Technology
Spectroscopic techniques were used to provide an in-depth analysis of dc magnetron sputtered hydrogenated amorphous silicon (a-Si:H) layers for photovoltaic applications. The complex optical dispersion in the range from 0.7 eV to 5.0 eV was determined using variable angle spectroscopic ellipsometry. A shift of the absorption onset to higher energies for samples sputtered at increased hydrogen flow rates is related to less defect states within the mobility gap. In order to calculate the hydrogen content of the deposited layers, the absorption due to silicon-hydrogen stretching vibrations was evaluated employing Fourier transformed infrared (FTIR) spectroscopy. A linear relationship between the absorption onset and the hydrogen concentration is observed. Raman spectroscopy confirms the purely amorphous nature of the silicon network. A deeper understanding of the states within the mobility gap is obtained from electrical spectroscopic techniques. Charge deep level transient spectroscopy measurements at various temperatures probe the defect level energy and concentration. Furthermore, a comparison with densities estimated by drive level capacitance profiling is provided.