Berlin 2012 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 5: Thin film photovoltaics: CIGSe + CdTe

DS 5.4: Vortrag

Montag, 26. März 2012, 10:45–11:00, H 2032

Impedance Spectroscopy of CdTe Thin Film Solar Cells — •Charlotte Weiss, Christoph Heisler, Udo Reislöhner, Carsten Ronning, and Werner Wesch — Institute of Solid State Physics, University of Jena, Max-Wien-Platz 1, D-07743 Jena

Impedance Spectroscopy (IS) is a widely used method to analyze dielectric properties of specimen as a function of frequency. Typically this characterization method delivers an equivalent circuit diagram of the device under examination to describe its electrical properties. Traditionally IS is used in coating evaluation, corrosion monitoring and in electrochemistry. During the last years the method became more important also in the field of electrical characterization of solar cells.

In our work we use IS for the electrical characterization of thin film CdTe solar cells. The measurement is done at room temperature without illumination in a frequency domain from 20Hz to 2MHz. The samples are measured under variable forward bias. The results match insufficiently with the model of two resistor-capacitor circuits in series which is commonly used to describe the p-n junction and the blocking back contact. For better consistency, other models from the literature are used and discussed. From the results a conclusion is drawn about the properties of the solar cell such as the nature of the p-n junction or the performance of the back contact.