Green GaInN photonic-crystal light-emitting diodes with small surface recombination effect

We have fabricated green GaInN light-emitting diodes (LEDs) containing two-dimensional photonic crystals (PCs). The PC structure is comprised of air holes that penetrate through the active layer. The observed emission intensity at room temperature was enhanced by a factor of ∼3 when a PC was introduced, which is close to the theoretical enhancement calculated without taking into account surface recombination at the air-hole edges. The carrier lifetime changes little when a PC is incorporated due to the low surface recombination. In contrast, the carrier lifetime in blue-emitting LEDs decreased by a factor of 4 when a PC was introduced. The surface-recombination velocity in green-emitting devices is estimated to be 3×102 cm/s, an order of magnitude smaller than in blue-emitting devices. This is due to the strong carrier localization effect in green-emitting GaInN.