Scaling issues of Schottky junction solar cells based on graphene and silicon quantum wires in the sub-10-nm regime

In this paper, a scaling study of heterojunction solar cells based on p-type silicon quantum wires with rectangular cross sections in the sub-10-nm regime and graphene (p-SiQWs/G) is presented. The scaling issues in p-SiQWs/G solar cells performance focusing on SiQWs diameter, the distance between SiQWs, and the number of graphene layers is investigated by a coupled optical and electrical model taking into account the quantum effects of SiQWs. A minimum efficiency of p-SiQWs/G solar cells is obtained for SiQWs with moderate diameter. The p-SiQWs/G solar cell with small diameter shows high efficiency because of wide band gap of SiQWs with small diameter. On the other hand, p-SiQWs/G solar cell with large diameter also shows high efficiency because of strong light absorption of SiQWs resulted from high surface area. The results also show that the denser packing of SiQWs and monolayer graphene improve the efficiency of p-SiQWs/G solar cells.