ALUMINIUM-DOPED ZINC OXIDE FILMS FOR SILICON THIN-FILM SOLAR CELLS PREPARED BY SPUTTER DEPOSITION FROM ROTATABLE CERAMIC TARGETS

摘要

We developed aluminium doped zinc oxide films for the application in silicon thin film solar cells andmodules. The ZnO:Al films were deposited by mid frequency magnetron sputtering from rotatable dual magnetrons withceramic ZnO:Al_2O_3 targets onto glass substrates. The production process is up-scalable to very large areas (> m~2) andpromises high throughput. In our system the normalized dynamic deposition rate was around 8.25 (nm·m)/(min·kW). Thedeposition conditions, in particular the substrate temperature and the discharge power, were varied to prepare films at highrates and to optimize them for use in thin-film silicon solar cells. The zinc oxide films exhibited a specific resistivity as lowas 3.8·10~(-4) Ω·cm and were highly transparent. First microcrystalline solar cells deposited onto texture-etched ZnO:Al filmsachieved an efficiency up to 7.2%. Note, that commercially available float glass served as substrate for these cells.