Improving the Performance of Free-pGaN Deep-Ultraviolet Light-Emitting Diodes by Embedding Self-Assembled Ni Nanoparticles Between p-AlGaN/p-Electrode

The performance for free-pGaN deep-ultraviolet light-emitting diodes (DUV LEDs) is still limited by total internal reflection (TIR), p-electrode absorption, and self-heating effect. In this study, we propose inserting a layer of self-assembled Ni nanoparticle array between p-AlGaN and p-electrode (Ni/Au). The experimental results demonstrate that compared to conventional DUV LEDs, the proposed device exhibits significant improvements in the optical power, forward voltage, and thermal characteristics. This is due to the fact that Ni nanoparticles serve as effective scattering centers, thereby enhancing the light extracting efficiency (LEE). In addition, the ohmic contact resistance between the p-electrode and p-AlGaN can be reduced effectively due to the thermal stress relaxation effect of Ni nanoparticles. Hence, the decreased p-electrode contact resistance and the increased LEE suppress the self-heating effect, resulting in a higher life reliability for DUV LED with Ni nanoparticles.