摘要
Wafer-scale SiO2 photonic crystal （PhC） patterns （SiO2 air-hole PhC, SiO2-pillar PhC） on indium tin oxide （ITO） layer of GaN-based light-emitting diode （LED） are fabricated via novel nanospherical-lens lithography. Nanoscale polystyrene spheres are self-assembled into a hexagonal closed-packed monolayer array acting as convex lens for expo- sure using conventional lithography instrument. The light output power is enhanced by as great as 40.5% and 61% over those of as-grown LEDs, for SiO2-hole PhC and SiO2-pillar PhC LEDs, respectively. No degradation to LED electrical properties is found due to the fact that SiO2 PhC structures are fabricated on ITO current spreading electrode. For SiO2- pillar PhC LEDs, which have the largest light output power in all LEDs, no dry etching, which would introduce etching damage, was involved. Our method is demonstrated to be a simple, low cost, and high-yield technique for fabricating the PhC LEDs. Furthermore, the finite difference time domain simulation is also performed to further reveal the emission characteristics of LEDs with PhC structures.
Wafer-scale SiO2 photonic crystal （PhC） patterns （SiO2 air-hole PhC, SiO2-pillar PhC） on indium tin oxide （ITO） layer of GaN-based light-emitting diode （LED） are fabricated via novel nanospherical-lens lithography. Nanoscale polystyrene spheres are self-assembled into a hexagonal closed-packed monolayer array acting as convex lens for expo- sure using conventional lithography instrument. The light output power is enhanced by as great as 40.5% and 61% over those of as-grown LEDs, for SiO2-hole PhC and SiO2-pillar PhC LEDs, respectively. No degradation to LED electrical properties is found due to the fact that SiO2 PhC structures are fabricated on ITO current spreading electrode. For SiO2- pillar PhC LEDs, which have the largest light output power in all LEDs, no dry etching, which would introduce etching damage, was involved. Our method is demonstrated to be a simple, low cost, and high-yield technique for fabricating the PhC LEDs. Furthermore, the finite difference time domain simulation is also performed to further reveal the emission characteristics of LEDs with PhC structures.
基金
Project supported by the National Basic Research Program of China (Grant No.2011CB301902)
