Numerical Approach to the Investigation of Performance of Silicon Nanowire Solar Cells Embedded in a SiO2Matrix

The electrical characteristics of silicon nanowire (SiNW) solar cells with p-type hydrogenated amorphous silicon oxide ( E g = 1.9 eV)/n-type SiNWs embedded in a SiO 2 /n-type hydrogenated amorphous silicon oxide ( E g = 1.9 eV) structure have been investigated using two- and three-dimensional device simulators, taking into account the quantum size effect. The average bandgap of a SiNW embedded in SiO 2 increased from 1.15 to 2.68 eV with decreasing diameter from 10 to 2 nm, owing to the quantum size effect. Note that under sunlight of AM1.5G, the open-circuit voltage ( V oc ) of SiNW solar cells also increased to 1.46 V with decreasing diameter of the SiNWs to 2 nm. This result suggests that it is possible to enhance V oc by applying the quantum size effect, and a SiNW is a promising material for all-silicon tandem solar cells.