Efficiency enhancement in the thin film GaAs solar cell using photonic crystal as a back reflector

Light trapping in the thin film solar cell has been studied for a while and is considered as among the most important parameter which may reduce the gap between the most efficient single junction thin film solar cell available till date and the theoretical Shockley-Queisser (SQ) Limit. Usually, metallic back reflectors are being used for the thin film solar cells. Here we are presenting an alternative method for single junction thin film GaAs solar cell using photonic crystals as a back reflecting mirror. We have used the photonic crystals (PhC) structure having GaAs rods having SiO₂ in the background, which has improved absorption in the near band edge wavelength. The results of the numerical modelling using FDTD algorithm clearly indicate the efficiency improvement as compared to the metallic reflector as back mirror material.