Divergent Far-Field III–Nitride Ultrathin Film-Transferred Photonic Crystal Light-Emitting Diodes

Abstract

The divergent far-field distribution of III-nitride ultrathin film-transferred light-emitting diodes (FTLEDs) with ellipse holes of triangular photonic crystal (PhC) lattice have been experimental and theoretical studies. Angular-and-spectral-resolved measurement revealed guided modes extraction behaviors which obtain good agreement with theoretical model according to two-dimensional free photon band structure. The azimuthal evolution of the guided modes' diffraction behavior according to Bragg's diffraction has also been discussed by angular-resolved monochromatical mapping. Finally, the PhC FTLEDs show light enhancement with the divergence far-field pattern that exhibited 130% at a driving current of 200 mA as compared with non-PhC (without PhC) FTLEDs. This could lead to promising LEDs with unusual divergent far-field properties for specific applications.

Ga(In)N Photonic Crystal Light Emitters with Semipolar Quantum Wells

“…9) Other groups already demonstrated the successful integration of photonic crystals into polar quantum well light emitters to improve the light extraction. 10,11) Typically, photonic crystals are used as light scatterer to out-couple guided modes very directionally. Such leaky modes can be used to improve the light extraction efficiency, but also for beam profile engineering.…”