GIXRF–NEXAFS investigations on buried ZnO/Si interfaces: A first insight in changes of chemical states due to annealing of the specimen

GIXRF–NEXAFS is a combination of X-ray spectroscopy methods which allows for a non-destructive, depth-dependant chemical speciation of layer systems in the range of a few to several hundred nanometers. We applied this technique to a model system for thin-film silicon solar cells, a Si/ZnO layer system, which was investigated in its as-deposited and its annealed state. By means of total reflection at the buried ZnO/Si interface we could gain access to chemical information on the interface. In addition, a diffusion of contaminants from the ZnO into the Si was observed after annealing.