Analysis of the physical processes that limit the reliability of GaN-based optoelectronic devices

This thesis reports the results of an extensive analysis of the reliability of GaN-based Light-Emitting Diodes (LEDs) and Laser Diodes (LDs). The analysis has been carried out in close cooperation with the manufacturers of the devices: for this reason, we have worked on state-of-the-art LEDs, lasers and R&D samples, providing a feedback to the manufacturer on the weaknesses of adopted technology. By means of specific experiments on suitable test structures, we have been able to separately analyze (i) the degradation of the LEDs active region, (ii) the role of passivation layer in limiting LEDs reliability, (iii) the degradation of the ohmic contacts of the devices, (iv) the degradation of the properties of LEDs package and resins and (v) the degradation of violet laser diodes and its dependence on driving conditions