  Localized surface plasmons (LSPs) have played a significant role in improving
the light emission efficiency of light emitting diodes (LEDs). In this report,
polygonal nanoholes have been fabricated in the p-GaN layer of InGaN-based LEDs
by using Ni nanoporous film as the etching mask, and then Au/Al metal
nanoparticles are embedded in the nanoholes to form the LSP structure. The
coupling between the LSP and the LED has been clearly observed. The results
show that the light output of the LEDs has been increased by 46% at higher
current injection condition, and together with a shift of the gain peak
position to the LSP peak resonance energy. As the coupling distance is
decreased from 60 nm to 30 nm, the maximum enhancement factor increases to
2.38. The above results indicate that the LSP from the polygonal metal
nanoparticles is a kind of very promising structure to enhance the lighting
performance of the InGaN-based LEDs.
