Cavity Plasmon: Enhanced Luminescence Effect on InGaN Light Emitting Diodes

TL;DR

This study demonstrates that polygonal nanohole-based cavity plasmons significantly enhance the luminescence and efficiency of InGaN/GaN LEDs, revealing a new shape-sensitive plasmon mechanism with potential for optoelectronic improvements.

Contribution

The paper introduces a novel cavity plasmon mechanism generated by polygonal microcavities, leading to enhanced LED performance and a longer emission lifetime.

Findings

Light output increased by 46% with current injection.

Maximum enhancement factor of 2.38 at reduced coupling distance.

Longer spontaneous emission decay time due to plasmon coupling.

Abstract

We fabricated polygonal nanoholes in the top p-GaN layer of the InGaN/GaN light-emitting diode, followed by the deposition of Au/Al metal thin film within the nanoholes to create metal microcavities, thereby constructing the surface plasmon structure. The findings indicate that with increased current injection, the light output of the LEDs rose by 46%, accompanied by a shift of the gain peak position towards the plasmon resonance energy. The maximum enhancement factor increases to 2.38 as the coupling distance decreases from 60 nm to 30 nm. Interestingly, time-resolved photoluminescence data showed that the spontaneous emission decay time lengthened due to the plasmon coupling, suggesting the presence of a new plasmon coupling mechanism. Finite-Difference Time-Domain simulation results show that the electric field is localized at certain locations around the metal microcavity, generating a new type of shape-sensitive plasmon, named Cavity Plasmon here. This intense localization leads to a longer lifetime and enhances the recombination efficiency of excitons. We discuss several unique properties of the cavity plasmon generated by the polygonal metal microcavity with several specific angular shapes. The results demonstrate that the cavity plasmon generated by the polygonal metal microcavity is a highly promising technique for enhancing the light emission performance of of relevant semiconductor optoelectronic devices.