Sputterheizung CdS-Kammer (Foto: Gabi Haindl)

Solar cells with alternative absorbers

The Surface Science group coordinates the joint research project PINET to develop alternative highly-absorbing compound semiconductors for thin film solar cells. Thin film solar cells on the basis of CdTe, CIGS and µc/a-Si are already commercially successful. To realize future solar cells with higher efficiencies and lower production costs, further solutions are desirable.

The device structure shall be realized as a p-i-n-setup, which has, on the basis of basic physical considerations, some principle advantages for energy conversion. The p-i-n structure consists of a quasi-intrinsic compound semiconductor and a p- and n-conductive hetero contact with wide band gaps. For n-type contacts, many different materials are available, whereas the material basis for the p-type contact is not satisfactorily resolved. Therefore it is necessary to identify new compound semiconductors, but also p-type electrode materials.

To ensure the functionality of the p-i-n solar cells, a suitable band alignment and the passivation of interface defects is important. A point of main effort is therefore the development of strategies to modify the interfaces.

The characterization of the solar cells and its single layers include the experimental analyses of the electronic structure and the morphological, electrical and optical properties as well as theoretical investigations of the electronic structure and defect properties.

The project is coordinated by Prof. Dr. Wolfram Jaegermann and Prof. Dr. Andreas Klein. The research partners of the PINET project are: