Theoretical study on effect of SiC crystal structure on carrier transfer in quantum dot solar cells

Quantum dot (QD) solar cells are proposed as high-efficiency solar cells. However, their reported conversion efficiencies have been lower than half of the ideal value. To improve their efficiency, the optimization of their cell structure in terms of various parameters, e.g., dot size, interdot distance, type of materials, and QD/bulk interface structure, is necessary. In this paper, we focused on the most important factor for the improvement in the conversion efficiency of Si/SiC type QD solar cells and investigated the effect of the atomistic structure of the QD/bulk interface on carrier transfer by tight-binding simulation. We constructed models of Si/SiC systems and analyzed the effect of QD/bulk interface defects on their electronic structure and carrier transfer properties. It was suggested that electrons trapped at the QD/bulk interface and the type of SiC crystal structure affect electron transfer.