Sputtering of thin pyrite films

摘要: The high production costs of conventional solar cells make it necessary to investigate alternative methods and materials with respect their suitability for energy conversion. Semiconductors absorption coefficients are favorite candidates because potential reduce material by using a thin film as active layer. One these is pyrite, which in the ideal case composition FeS 2 has an extraordinary optical coefficient (a>~6x 105 cm -1 hv> 1.3 eV) [1]. A pyrite 0.1 ~m thickness absorbs more than 99% sunlight (AM 1.5) makes very promising cell applications. band gap synthetic crystals was measured [1,2] be 0.92 0.95 eV and, at room temperature, electron mobilities range from 100 360 cm2/V s were found [3]. Problems arise connection open circuit voltage Uoc photoelectrochemical [1] limited 0.2 V until now. In principle should possible yield half [4], i.e. ca. 0.45-0.5 expected. Since efficiency proportional Uo~ this quantity must enhanced valuable technical small values perhaps due difference Fermi levels between electrolyte used (iodide-iodine). This assumption supported recent electro-reflectance measurements [5]. Another explanation concerns strong non-stoichiometry that can lead sulfur deficiency percentage shown works [6,7]. defects simple point ligand field theory predicts development electronic defect states