Development of advanced transparent conductive electrodes for large-area opto-electronic devices

The need for transparent electrodes as electrical contacts for inorganic and organic light emitting diodes, solar cells and flat panel displays is strongly increasing due to the extensive market growth in these areas. The solutions available on the market today fulfill the demands on low resistivity, high transmittance,large area deposition,low cost manufacturing,and ability for fine patterning, light scattering and precise alignment of the electronic structure to surrounding semiconductors only partially. The coopereration of five Fraunhofer Institutes aims towards achieving fundamental knowlegde and control about the defect chemistry and morphology of the transparent semiconductive oxides to manufacture materials with outstanding proterties such as ZnO:Al film with doping efficiency >80%, n-type TCO films based on TiO2:Nb and Zn-stannates and Ag-based multilayers. New TOCs will be developed using advanced PVD and Sol-Gel techniques. Using these new materials for device applications, we expect a strong impact towards more advanced and more efficient products. First results of our work addressing band structure simulation, material and process development will be shown.