III-nitride light-emitting diode with embedded photonic crystals

– KH Li, KY Zang, SJ Chua, and HW Choi

(a) Schematic diagram showing the structure of an LED with embedded PhC; FE-SEM images showing (b) the edge region of the ELO regrown GaN layer covering the nanopillar array and (c) cross-sectional view the nanopillars planarized by the ELO layer.

Applied Physics Letters, vol. 102, 18, pp. 181117 (2013)

A photonic crystal has been embedded within an InGaN/GaN light-emitting diode structure via epitaxial lateral overgrowth of a p-type GaN capping layer. The photonic crystal is a hexagonal-closed-packed array of nano-pillars patterned by nanosphere lithography; the capping layer planarizes the disconnected pillars to form a current-injection device. Optical properties of the nanostructures and devices are extensively studied through a range of spectroscopy techniques and simulations. Most significantly, the emission wavelengths of embedded photonic crystal light-emitting diodes are nearly invariant of injection currents, attributed to partial suppression of the built-in piezoelectric in the quantum wells.

DOI: 10.1063/1.4804678