Enhancement in external quantum efficiency of blue light-emitting diode by photonic crystal surface grating

Abstract
Blue photonic crystal light-emitting diodes were evaluated with photonic crystal hole patterns. The diameter of the holes, lattice constant, and emission wavelength were selected to be 110, 220 and 450 nm, respectively, to attain a maximum enhancement in the wall-plug efficiency. The improvement in external quantum efficiency was 30–50%. Changes in voltage characteristics caused by the etched holes were found to be correlated with increased leakage current.