Optical and Electrical Simulation Studies of Light Trapping in GaAs Thin Film Solar Cells Using 2D Photonic-Crystal

The paper presents and analyzes the study by optical and electrical simulations, the impact of introducing a 2D Photonic-Crystal (PhC) made of a GaAs rods embedded within a silica matrix and placed on the backside of a GaAs thin film solar cell. The goal is to create a broadband reflector inducing a weak parasitic absorption and that could also serve for light-trapping purposes. A solar cell based on a planar aluminum reflector is used as a reference. The optical and electrical properties of the resulting cells are numerically investigated in order to discuss the potential of this approach. Those factors that reduce the efficiency of a GaAs cell are also considered in the presence of PhC back reflector as well as in Aluminium reflector and found that the degradation in the efficiency of the PhC solar cells even in worst case is less and thus the cell performs better than metallic reflector. The results shows that the 2D PhC configuration proposed could have a real potential for enhancing the efficiency of such cells. Well known Plane Wave Expansion method and FDTD methods have been used to optimize the structure of GaAs solar cells.