AVS 50th International Symposium
    Thin Films Wednesday Sessions
       Session TF2-WeA

Invited Paper TF2-WeA1
Magnetron Sputtering for II-VI Semiconductor PV Materials

Wednesday, November 5, 2003, 2:00 pm, Room 329

Session: Optical Thin Films and Photovoltaics II
Presenter: A.D. Compaan, University of Toledo
Correspondent: Click to Email

The deposition of polycrystalline, thin-film, II-VI semiconductors such as CdTe is possible by many different techniques, but the use of a plasma-based method such as magnetron sputtering can have significant advantages. In this paper we review recent advances in the fabrication of CdS/CdTe cells using rf planar magnetron sputtering and discuss some of the advantages that accrue from the use of sputtering in this class of materials. Some of these advantages take on increased relevance as the polycrystalline thin-film community begins to address issues related to the challenges of fabricating high efficiency tandem cells with efficiencies over 25%. Recently we have achieved improved sputtered cell performance (Voc= 814 mV, Jsc=23.5 mA/cm2, fill factor = 73.25, and efficiency = 14.0%) from superstrate cells based on window layers with sputtered ZnO:Al. In addition we have used reactive sputtering for the deposition of nitrogen-doped layers of p-ZnTe for possible use in transparent back contacts to CdTe. We shall also discuss recent results in the sputtering of wider and narrower bandgap alloys of CdTe with Zn, Mn, and Hg, and in the fabrication of cells with very thin CdTe layers having relatively little loss in performance and stability. Finally, the use of magnetron sputtering permits the fabrication of flexible thin-film cells on temperature-sensitive substrates such as polyimides. Work supported by the National Renewable Energy Lab and the U.S. Air Force.