10.14279/depositonce-5184
Open Accesn Version

Abstract:
Liquid phase crystallization is a promising technology to grow multicrystalline silicon thin films on glass substrates. As part of this work the influence of various sample stacks and materials were examined and their influence on the process window for line-shaped continuous wave laser crystallization is shown. A phase diagram for the crystallization of 10 µm thick silicon layers was recorded and several working points investigated in terms morphology. It is shown that optimized crystallization parameters lead to absorber layers with a preferential grain orientation towards the surface normal and in scanning direction of the laser accompanied by a strong reduction of high angle grain boundaries and the overall grain boundary density. Those morphological changes are correlated to the optoelectronic properties on a device level and ultimately led to a stable record efficiency of 11.8 % for a 9 µm p-type silicon thin film solar cell. A detailed lifetime analysis on a state of the art device was performed in order to identify the origin of low lifetime regions. Subsequently various seed layer crystallization methods are introduced to further improve the material quality. This ultimately resulted in a significantly improved grain sizes, even stronger preferential texture formation and improved electrical properties confirmed by first photoluminescence imaging and Hall measurements.