Preparation of CuInS{sub}2 absorber layers by rapid thermal sulfurization using H{sub}2S and DTBS

摘要

CuInS{sub}2 and Cu(In, Ga)S{sub}2 absorber layers were prepared by a 2-stage process using sputtered or evaporated metallic precursors. Using a reactive atmosphere containing H{sub}2S or Ditertiarybutylsulfide (DTBS), the sulfurization was performed in a rapid thermal process (RTP) system. The influence of the precursor structure and the sulfurization process parameters on the properties of the absorber layers and the photovoltaic performance of the corresponding solar cell devices were investigated. The most critical effect, which lies in a segregation of in the initial state of the sulfurization, can be overcome by using appropriate precursor structures or by the incorporation of Ga. Using sequentially evaporated Cu/in precursors, efficiencies in the range of 10% could be obtained in a wide process window. The incorporation of Ga opens the possibility to tailor the Ga gradient within the absorber and therefore the Voc of the device. A higher reproducibility and also higher efficiencies (11.6% total area) were obtained in the case of Cu(InGa)S{sub}2 absorbers.