// ODIN CIGS
There is still a high physical and technological potential for development in the Cu(In,Ga)Se2 photovoltaic technology (CIGS). The overarching goal of the project ODIN CIGS is therefore to identify crucial parameters which can further improve the power conversion efficiency of CIGS cells and modules. Through a better understanding of CIGS growth and the influence of the interfaces on the efficiency, especially at the pn-junction, a new best value of 23.5% for cells is to be achieved. Once the optimized processes and process sequences are identified for cells, they will be scaled up to a module size of 30x30 cm2 with a target efficiency of 18.5%.
The scientific and technical project goals involve improving the CIGS absorber by reducing growth-related defects and by further improving process control, thereby identifying new possibilities for raising efficiency values. Likewise, the pn-junction is to be optimized through mutual adaptation of the CIGS-surface and a Zn-based buffer system, which as of today is still contains a sulfidic and an oxidic partner. The aim is to simplify the process sequence to require only one n-partner. The sulfidic n-partner is based on Zn(O,S) and the deposition methods of by chemical bath deposition (CBD), sputtering, and the very gentle atomic layer deposition process (ALD) will be evaluated comparatively. The ternary ZnO-based buffers of the type (Zn,M)O with M=Mg, Sn, Ti are explored as oxidic n-partners. Learning from Si-technology, the back contact interface will be electrically passivated and at the front contact the optical absorption will be reduced through the application of a hydrogen-doped indium oxide material.
All technical process variations are accompanied by extensive material-analytical and electro-optical studies. In this way, the researchers will gain an advanced understanding of loss mechanisms and their influence on the photovoltaic device.
