Photon confined systems in the form of microcavities and photonic crystals overcome the main stumbling block to high efficiency light emitters, i.e. the extraction of photons from high-index materials. On the more fundamental side, they lead to the modification of lifetime for sharp transitions (the Purcell effect), recently observed for quantum dots in micropillars, and to strong light-matter coupling for quantum wells embedded in planar microcavities.
InGaN Quantum Dots for High Efficiency Blue and Green Light Emitters