Regensburg 2004 – scientific programme

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DS: Dünne Schichten

DS 22: Postersitzung

DS 22.51: Poster

Tuesday, March 9, 2004, 14:30–17:00, Poster B

CuInS_2 Solar Cells Deposited by Reactive Magnetron Sputtering — •Thomas Unold, Jan Hinze, and Klaus Ellmer — Hahn-Meitner Institut, Glienicker Str. 100, D-14109 Berlin, Germany

We have deposited CuInS_2 films in a reactive magnetron sputtering system, specially designed for the deposition of sulfides by sputtering in Ar-H2S mixtures. The substrate temperature was varied from 350 to 500C and the deposition rate was about 50 nm/min. The magnetron plasma was excited by a DC power supply. The contacts (Mo, ZnO/ZnO:Al) and the buffer layer (CdS) were prepared by the standard processes of the Hahn-Meitner-Institut. Up to now solar cell efficiencies of up to 8.1 have been obtained. The electronic and optical properties of the solar cell devices were analyzed by dark and illuminated current-voltage characteristics, quantum efficiency and photoluminescence measurements. We find that although the short circuit current is comparable to that of cells prepared by the two-step process (sulfurization of sputtered precursor metals), the open-circuit voltage is about 100meV lower. This is consistent with the quantum efficiency analysis where we find a decreased collection efficiency at long wavelengths compared to cells from the two-step process. From photoluminescence we conclude that the efficiency of our cells is limited by the defect density in the absorber layer.