In crystalline silicon (c-Si) solar cell field, an intensive effort is being paid to reduce the quantity of silicon material used in each cell in order to minimize its costs. With the reduction of wafer thickness, light trapping inside the c-Si absorber becomes more and more necessary. Several photonic structures have been proposed underlining their optical properties. However, addressing other technological issues, like contact formation through the photonic structure, is also necessary for their application into finished devices. In this paper we study the viability of laser firing technique to create solar cell base contacts through inverse opals deposited on the previously passivated rear surface of the device as photonic light trapping structures. Firstly, we check out that electrical surface passivation properties are not degraded during the inverse opals fabrication steps. Next, from SEM images we deduce that the inverse opal is mechanically and thermally stable after laser processing. Moreover, reflectance measurements show that optical properties are also maintained. From these results, we can conclude that inverse opal fabrication is compatible with solar cell technology and that contacts can be created by laser means without damaging the surrounding 3D inverse opal structure neither the silicon below it.

Peer Reviewed