Nanocrystalline diamond on Si solar cells for direct photoelectrochemical water splitting

This article presents a study of a boron-doped nanocrystalline diamond (B-NCD) and crystalline silicon solar cell (c-Si SC) heterostructure designed for direct photoelectrochemical water splitting application. A system is proposed which generates voltages sufficient for water-splitting via light absorption by solar cells. The rear side (photo-anode) of the c-Si solar cell was shielded with the B-NCD layer intended to serve as a protective coating to eliminate corrosion of the Si and operate as a p-type conductive electrode suited for water decomposition. Information on the efficiency of the c-Si/B-NCD heterostructure and the distribution of the electric potential has been gained through investigation of minority carrier recombination mapping. The results of the B-NCD layer characterization by Raman spectroscopy, AFM, SEM and optical reflection measurements are presented. It is demonstrated that inclusion of a boron (p+) diffusion layer into a c-Si solar cell structure prevents lifetime (LT) degradation caused by the B-NCD deposition process. In addition it is shown that the B-NCD deposition temperature has a substantial effect on the properties of c-Si solar cell. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim