High photo-current generation in a three-dimensional silicon quantum dot superlattice fabricated by combination of bio-template and neutral beam etching for quantum dot solar cell

A Quantum Dot Superlattice (QDSL) offers high prospect for new generation photovoltaics. We fabricated and characterized a 3-dimensional array of Si-NDs as a QDSL with a high-aspect ratio, clear interface, and uniform size by using our advanced top-down technology consisting of bio-template and neutral beam etching processes for high-efficiency solar cells. Conductive atomic force microscopy measurements revealed that the conductivity became higher as the arrangement was changed from single Si-ND to 2D and 3D arrays with the same matrix of SiC, i.e. the coupling of wave functions was changed. Moreover, we measured the contribution of 3D Si-NDs array in producing photocurrent inside a quantum dot solar cell and also observed a higher photo absorption of sunlight by 3D Si-NDs (30%) than by a 2D array of Si-NDs (10%).