Interface properties of chalcopyrite heterocontacts

Interface properties of heterocontacts determine the device performance of thin film solar cells. We investigated well defined chacopyrite interfaces and heterocontacts of MBE grown samples by electron spectroscopy to obtain informations on the morphology and electronic properties of the contact phases. In particular CuInSe2 and CuInS2 (001) and (112) surfaces were grown by MBE and studied with respect to contact formation to ZnO, ZnS and ZnSe. Due to Cu back diffusion into the bulk even for stoichiometric samples Cu poor interfaces were observed giving rise to interdiffused Zn3In2X6 (X=S,Se) layers in the contact plane. Band alignments obtained fort the prepared heterocontacts will be compared to models given by M\"{o}nch and Wei et al. The influence of contact preparation on the properties of the interface will be discussed in detail.