Improving the Vertical Light Extraction Efficiency of GaN-Based Thin-Film Flip-Chip LED With Double Embedded Photonic Crystals

The vertical light-extraction efficiency (LEE) of the thin-film flip-chip light-emitting diodes with the embedded photonic crystal (PhC) is investigated using the finite-difference time-domain method. This paper systematically analyzes the dependence of the vertical LEE on the vertical structure and the embedded PhC parameters. It is found that the introduction of the p-side embedded PhC and n-side embedded PhC does not significantly destroy the microcavity resonant effects. In particular, a twofolds enhancement in the vertical LEE is obtained for the optimized structure by scanning the double embedded PhCs parameters and the physical mechanisms for the enhancement of the vertical LEE are discussed.