24 research outputs found
Lithographic processing of photonic crystal structures on GaN epilayers for LED applications
Lithographic processing of photonic crystal structures on GaN epilayers for LED applications
Nanoimprint lithography patterning of photonic quasicrystal light extraction structures on InGaN/GaN blue LEDs
Photonic crystal (PhC) and photonic quasi crystal (PQC) light extraction structures for enhanced efficiency and beamshape control in light-emitting devices
Modelling, fabrication and characterisation of photonic quasicrystal structures on GaN LEDs
Photonic quasi-crystal light emitting diodes: comparisons of device performance with pattern pitch
In this paper we discuss theoretical modelling methods for the design of photonic crystal and photonic quasi-crystal (PQC) LEDs - and apply them to the analysis of the extraction enhancement performance and shaping of the emitted beam profile of PQC-LED structures. In particular we investigate the effect of the pitch of the PQC patterning, and consider the physical mechanisms giving rise to performance improvements. In addition, we examine the relative contributions to performance improvements from effective index reduction effects that alter the conditions for total internal reflection at the device air interface, and from photonic crystal scattering effects that give rise to radically improved extraction performance. Comparisons are made with the performance of recently fabricated devices