Gallium Arsenide Solar Cell Absorption Enhancement Using Whispering Gallery Modes of Dielectric Nanospheres

Based on a perfectly flat gallium arsenide solar cell, we show that it is possible to modify the flow of light and enhance the absorption without modifying the active material structure or degrading its electrical properties. The sunlight couples into confined resonant modes formed by a periodic arrangement of dielectric nanospheres above the solar cell. The in coupling element is lossless and, thus, has the advantage that no energy is lost within the dielectric nanospheres. This stored energy is absorbed by the underlying active material which directly contributes to the photocurrent enhancement of the solar cell.