Sequential processes for the deposition of polycrystalline Cu(In,Ga)(S,Se) 2 thin films: Growth mechanism and devices

• Published in: Solar energy materials and solar cells Vol. 41; pp. 355 - 372
• Main Authors: Walter, T., Braunger, D., Dittrich, H., Köble, Ch, Herberholz, R., Schock, H.W.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1996
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/0927-0248(95)00103-4

Sequential processes for the fabrication of polycrystalline Cu(In,Ga)(S,Se) 2 thin films using (In,Ga) x (S,Se) precursors are presented and discussed. Depending on the deposition conditions and the source material, different In x S precursor films for the formation of CuInS 2 can be obtained. For In/(In + Cu) > 0.5 the reaction pathway of CuInS 2 thin films follows the Cu 2S In 2S 3 pseudobinary tie line after the indiffusion of Cu and S independent of the composition of the InXS precursor. A Cu-rich step resulting in the segregation of CuS is accompanied by a recrystallization of the entire film. The coverage of CuInS 2 with CuS is more complete for the sequential process as compared to codeposited thin films. The device performance of devices based on Cu(In,Ga)(S,Se) 2 grown by codeposition and by sequential processes is comparable.