Structural Effects on the Photonic Band Structure of Two Dimensional Photonic Crystal

The Photonic band structure of two dimensional Photonic Crystal is calculated using Plane Wave Expansion Method. The structure of the photonic crystal has been varied by changing the radii of the dielectric rods. Three cases have been taken corresponding to different structural forms of silicon, namely c-Si, poly-Si and a-Si materials. The variation of bandgap-to-midgap ratio has been calculated for the fill factor and dielectric contrast. The bandgap to midgap ratio is found to be maximum for a-Si/air structures and shifted to lower values for poly-Si/air and Si/air structures. The results have been explained using the defect migration occurring due to phase transformation from amorphous to crystalline state.