Lattice Constant Effect of Photonic Crystals on the Light Output of Blue Light-Emitting Diodes

Photonic crystal (PC) slabs with triangular lattice constants of 230, 345, 460, and 690 nm have been fabricated onto InGaN–GaN multiquantum-well light-emitting diodes with a wavelength of 461 nm. For the shallow nanoholes in the depth range of 10–38.5 nm, the current–voltage characteristics were not changed but the electroluminescence intensities were enhanced by a factor of 3.5. The light output was most enhanced with the lattice constant corresponding to the wavelength due to the PC diffraction with constructive interference but was suppressed with the lattice constant of the half wavelength by forming a photonic bandgap.