Joint Center For Artificial Photosynthesis Seminar

III-V semiconductor compounds are well established in high-performance multi junction solar cells and also constitute a promising absorber material class for solar-driven water splitting due to their tunable electro-optical properties. Challenges for solar device-relevant breakthrough technologies such as the merge of silicon and III-V technologies, or the design of critical interfaces, or quantum structures are always associated with an adequate interfacial preparation and analysis. One of the fundamental problems for III-V-on-Si growth relates to the difference in atomic structure, which manifests itself in the polarity of the III-V material as opposed to the non-polar nature of the silicon substrate. Appropriate optical in-situ spectroscopy can facilitate adequate atomic scale in-situ growth control for the preparation of abrupt interfaces, which are essential for high-efficiency applications. Aiming for a water splitting tandem structure on silicon, our concept of III-V based structures on silicon substrates relies on suitable interface preparation and control on atomic length scales during heteroepitaxy. With Si as bottom cell, lattice-matched GaPN is a promising candidate for the top cell. Moreover, I will discuss the concept of a core-shell-shell nanowire absorber structure.