Hot-electron induced degradations in GaN-based LEDs fabricated on nanoscale epitaxial lateral overgrown layers

We report investigations on the hot-electron hardness of GaN-based multiple quantum wells (MQWs) fabricated on nanoscale epitaxial lateral overgrown (NELO) GaN layers. This layer was deposited using a SiO₂ growth mask with nanometer-scale windows. The active regions of the devices consist of five-period GaN/InGaN MQWs. Structural analyses of the material indicate significant reduction in the threading dislocation density of the devices compared to the control which were fabricated without the use of the NELO GaN layers. The hot-electron degradation of the devices due to the application of a large dc. current was characterized by detailed examination of the electroluminescence (EL), I-V, thermoreflectance and the current noise power spectra of the devices as a function of the stress time. Significant improvements in the hot-electron hardness were observed in the device compared to the control.