InGaN light-emitting diodes of micro-ring geometry

The fabrication and performance of an InGaN light-emitting diode (LED) array based on a micro-ring device geometry is reported. This design has been adopted in order to increase the surface area for light extraction and to minimize losses due to internal reflections and re-absorption. Electrical characteristics of these devices are similar to those of a conventional large-area LED, whilst the directed light extraction proves to be superior. In fact, these devices are found to be more efficient when operated at higher currents. This may be attributed to improved heat sinking due to the large surface area to volume ratio. The potential applications of these devices are also discussed.