Thin film CdTe solar cells by close spaced sublimation: Recent results from pilot line

CdTe is an attractive material to produce high efficient and low cost thin film solar cells. The semiconducting layers of this kind of solar cell can be deposited by the Close Spaced Sublimation (CSS) process. The advantages of this technique are high deposition rates and an excellent utilization of the raw material, leading to low production costs and competitive module prices. CTF Solar GmbH is offering equipment and process knowhow for the production of CdTe solar modules. For further improvement of the technology, research is done at a pilot line, which covers all relevant process steps for manufacture of CdTe solar cells.Herein, we present the latest results from the process development and our research activities on single functional layers as well as for complete solar cell devices. Efficiencies above 13% have already been obtained with Cu-free back contacts. An additional focus is set on different transparent conducting oxide materials for the front contact and a Sb2Te3 based back contact.

► Laboratory established on industrial level for CdTe solar cell research
► 13.0% cell efficiency with our standard front contact and Cu-free back contact
► Research on ZnO-based transparent conducting oxide and Sb2Te3 back contacts
► High resolution scanning electron microscopy analysis of ion polished cross section