Enhanced light extraction efficiency from AIGalnP thin-film light-emitting diodes with photonic crystals

摘要

We investigate the use of photonic crystals for light extraction from high-brightness thin-film AIGalnP light-emitting diodes with different etch depths, lattice constants, and two types of lattices (hexagonal and Archimedean). Both simulations and experimental results show that the extraction of high order modes with a low effective index n_(eff) is most efficient. The highest external quantum efficiency without encapsulation is 19% with an Archimedean A7 lattice with reciprocal lattice constant G=1.5 k_0, which is 47% better than an unstructured reference device.