Provided herein are photonic devices configured to display photonic band gap structure with a degenerate band edge. Advantageously, the microstimulator does not need to be physically modified. Means for determining the ceiling height are utilized to adjust the height of the piggyback conveyors. Through the electric field controller connected at both sides of the upper electrode of the pixel electrode, quality of display image can improve without a darkening area occurring at one part of the unit pixel.