Hierarchical structures consisting of SiO₂ nanorods and p-GaN microdomes for efficiently harvesting solar energy for InGaN quantum well photovoltaic cells

We experimentally and theoretically demonstrated the hierarchical structure of SiO₂ nanorod arrays/p-GaN microdomes as a light harvesting scheme for InGaN-based multiple quantum well solar cells. The combination of nano- and micro-structures leads to increased internal multiple reflection and provides an intermediate refractive index between air and GaN. Cells with the hierarchical structure exhibit improved short-circuit current densities and fill factors, rendering a 1.47 fold efficiency enhancement as compared to planar cells.