Fabrication Of Surface Nanosturctures And Study Of Mechanisum Of Surface Plasmon Enhanced Emission Of InGaN-based LED

In recent years, there has been remarkably rapid progress in the development of high brightness light-emitting diodes (LEDs) based on InGaN/GaN multiple quantum wells (MQWs). However, to attain the long-term performance targets, great efforts will need to achieve high emission efficiency. Among many recent approaches to the improvement of IQE, localized surface plasmon (LSP) enhanced emission has been actively studied. In this dissertation, surface plasmon enhanced LEDs with nanoporous surface structures were fabricated and the mechanisms of emission enhancement were studied. These LSP enhanced LEDs possess not only a well application prospect, but aslo the important theoretical significance for the studies of the mechanisms of surface plasmon enhancement.In this dissertation, Ni nanoparticles and nanoprous masks were prepared, and the factors affecting the surface morphology of Ni masks were studied. InGaN/GaN multiple quantum wells (MQWs) nanorods were prepared using Ni nanoparticle mask and the influence of dry etching to the internal quantum efficiency (IQE) was studied. Furthermore, the surface plasmon enhanced LEDs were fabricated using Ni nanoprous mask at an optimized dry etching condition, and the mechanisms of surface roughening enhanced and LSP enhanced emission were analyzed. Several scientific research achievements have been obtained:(1) We have mastered the surface morphology variation law of the Ni film in rapid annealing process on diffrient surface (GaN, sapphire and SiNx) under different Ni film thickness, annealing time and annealing temperature. Meanwhile, the Ni nanoporous mask with polygonal pore size of about180nm was obtained.(2) We have mastered the law of influence of dry etching damage to the internal quantum efficiency of nanorods MQWs. The internal quantum efficiency of nanorods MQWs were decreased significantly as RF power increased, which can be slightly influenced by ICP power. The internal quantum efficiency of nanorods MQWs showed a5.6times decrease substantially as the RF power increased from3W to100W and it can be slightly influence by ICP power with a30%variation in a wide ICP power range between30W and600W.(3) The LSP enhanced blue InGaN-based LEDs with metal nanoparticles embedded in the nanopores of the p-GaN surface were fabricated using Ni nanoporous templates. The optical output power of blue LEDs with Au/Al particles and Au particles and wild-spectra LEDs with Au/Al particles were enhanced by46%,72%and52%compared to the conventional LEDs by the coupling between LSP of metal particles and Electron-hole pairs in the MQWs which could enhance the spontaneous emission rate and the surface scatting effect which could enhance the light extraction efficiency. Emission enhancements were dependent on the LSP coupling distance between metal particles and MQWs, the maximum emission enhancement increased and shifted to LSP resonance energy with the distance decreased from60nm to30nm.