Transparent Conducting Oxides (TCO)

Main focus of our research on transparent conducting oxides (TCOs) is the implementation of aluminum-doped zinc oxide ZnO:Al as a transparent electrical front contact in polycrystalline silicon thin film solar cells.

Cooperations

Our research is embedded in multiple cooperations with industrial and public partners. One main focus is set with the joint research project “Light Management”, which studies the light trapping in silicon-based thin film solar cells. The project is funded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (grant no. 0327693H).

Preparation

The ZnO:Al is deposited on the glass substrate by magnetron sputter deposition. Hereafter the thin silicon films are deposited on top, which actually form the solar cell. The amorphous deposited silicon films are transformed into polycrystalline material by high-temperature-treatments (solid phase crystallization SPC 24 hours @ 600°C and rapid thermal annealing RTP 60 seconds @ 950°C). What happens to the zinc oxide in the layer stack and how the interface of the zinc oxide to the silicon behaves upon these high-temperature processes are central issues of our research.

Interface analysis with synchrotron radiation

The analysis of the Silicon/ZnO:Al-interface is carried out with synchrotron-based techniques. X-Ray emission and absorption as well as photoelectron spectroscopy at very high kinetic energies for example at the electron storage ring for synchrotron radiation BESSY II are methods for investigating the buried interfaces.

Results: High-Mobility ZnO:Al