Enhanced luminescence efficiency of GaN:Eu-based light-emitting diodes by localized surface plasmons utilizing gold nanoparticles

We demonstrate the enhancement of luminescence efficiency in GaN:Eu-based light emitting diodes (LEDs) by surface plasmons utilizing gold nanoparticles (NPs). A gold thin film is deposited on a GaN:Eu layer and subsequently thermal-annealed to form gold NPs. The size of the NPs can be controlled by changing the thickness of the films. The room-temperature photoluminescence (PL) intensity of the GaN:Eu LEDs with the NPs increases by 1.42-times compared with those without the NPs when the film thickness is 15 nm, which is attributed to enhanced light extraction efficiency due to coupling with localized surface plasmons. Time-resolved PL spectra at 10 K of the LEDs with the NPs show a shorter lifetime, supporting the existence of the coupling with local surface plasmons. The injection current-light output intensity profiles of the LEDs with the NPs shows 1.3-times enhancement of the output power due to coupling with local surface plasmons.