Thin CuInS2 films prepared by MOMBE:: Interface and surface properties

CuInS2 films were prepared on Si(111) by MOMBE using standard MBE Cu and In sources and Ditertbutyldisulfide (TBDS) as an organic sulfur precursor. The films were analyzed in situ by XPS, LEED and UPS. Deposition at 250 degrees C yields chalcopyrite films [1] with admixtures of CuSi2 and CuIn alloys. Deposition at higher temperatures up to 550 degrees C was used to clarify the feasibility of the process. High quality LEED diffraction patterns show epitaxial growth but CUSi2 precipitations are still observed for deposition on Si(111). A buffer layer of indiumsulfide showed no considerable effect on the interface morphology. The obtained LEED pattern are in accordance with the epitaxial relation Si {111}parallel to CuInS2{112}. Even for temperatures as high as 550 degrees C no incorporation of Carbon or residual hydrocarbons in the film or adsorbed at the surface were detected.