Effect of miniband formation in a quantum dot super lattice fabricated by combination of bio-template and neutral beam etching for high efficiency quantum dot solar cells

We studied the fabrication of a true silicon three-dimensional quantum dot super lattice (3D QDSL) by combination of bio-template and neutral beam etching, characterized it with respect to its photovoltaic performance, and realized its quantum effect. The existence of Si QDs was confirmed by using a bright field scanning transmission electron micrograph, and then a theoretical study proved the miniband formation inside our 3D QDSL. A drastic improvement in the photocurrent and efficiency of the p-i-n solar cell with QDSL showed a large electron transport and low series resistance by the vertical miniband formation inside the super lattice structure. Wide range of optical transition by QDs array in the QDSL was also observed in the external quantum efficiency of the QD solar cell.