CuInS2 based thin film solar cells with sputtered Zn,Mg O buffer

In a standard chalcoyprite based thin film solar cell, the formation of the heterojunction is mediated by a thin buffer layer. This buffer is prepared by chemical bath deposition of CdS. The cell is completed by an undoped ZnO film followed by the highly doped transparent front contact. We have developed an alternative concept without any buffer layer where the undoped ZnO is replaced by Zn,Mg O. By applying the concept to CuInS2 absorbers from industrial pilot production we achieved efficiencies of 8 for small area cells as well as monolithically integrated test structure