Defects and charge dynamics in 3C- and 4H-SiC investigated by surface photovoltage spectroscopy – photoelectrochemical / photocatalytic water splitting

Photoelectrochemical (PEC) and photocatalytic (PC) water splitting for hydrogen and/or oxygen generation is leading the way not only to green hydrogen production, but also to oxygen generators working solely on water basis. The quest for stable materials that can work with solar light as a basis has identified two superior photoactive material candidates, namely silicon carbide (SiC) and copper oxide (Cu₂O) materials, based on a number of criteria such as cost, abundancy, toxicity and sustainability. The optimum photoelectrical conversion electrode is often a very complex system, where the focus is on a very fast separation of the generated charges in order to increase the current densities out of the cells. The charge dynamics of the complex systems, be it on SiC, Cu₂O or any other photoactive material, can best be measured using time resolved surface photovoltage spectroscopy/measurements.

The SPVcheck tool is again the optimum choice, because it can be configured in a flexible way concerning sample geometry and energy selection range. A 2 UV/VIS light source (480 and 660 nm) approach can give a lot information about the charge dynamics in the photoelectrode and can be used to check the quality of the photoelectrical conversion electrodes in a high-volume production setup.