Berlin 2012 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 44: Poster IV: Thin film photovoltaics; Organic electronics and photovoltaics (jointly with CPP, HL, O); Organic thin films; Trends in atomic layer deposition (Focused session)

DS 44.11: Poster

Freitag, 30. März 2012, 09:30–12:00, Poster E

Photoluminescence measurement of polycrystalline CdTe made of high purity source material — •Hannes Hempel, Christian Kraft, Christoph Heisler, Sebastina Geburt, Carsten Ronning, and Werner Wesch — Institute of solid state physics, Friedrich Schiller Universität Jena, Helmholtzweg 3, 07743 Jena

CdTe is a common material for thin film solar cells. However, the mainly used CdTe source material is known to contain a high number of intrinsic defects and impurities. In this work we investigate the defect structure of high purity CdTe by means of Photoluminescence, which is a common method to detect the energy levels of defects in the band gap of semiconductors. We used a 633nm HeNe-Laser at sample temperatures of 8 K. The examined samples were processed in a new vacuum system based on the PVD method. They yield significantly different spectra on as-grown samples compared to those measured on samples which are grown by the standard process, since the double peak at 1,55eV was hardly detectable and the A-center correlated transition vanished. Instead a peak at 1,50eV with pronounced phonon coupling was observed. The 1,50eV peak is known from other measurements but has not been characterized so far. The intention of this work is to characterize this new feature and the influence of post deposition treatments of the CdTe layers on the PL spectra.