Localized surface plasmon enhanced quantum efficiency of InGaN/GaN quantum wells by Ag/SiO_2 nanoparticles

Lee-Woon Jang,Jong-Hyeob Baek,Jung-Hoon Song,In-Hwan Lee,Jin-Woo Ju,Jin-Kyu Yang,Dong-Seob Jo,Dae-Woo Jeon,Trilochan Sahoo,Alexander Y Polyakov,Seung-Jae Lee

doi:10.1364/oe.20.002116

Abstract

Optical properties of InGaN/GaN multi-quantum-well (MQW) structures with a nanolayer of Ag/SiO2 nanoparticle (NP) on top were studied. Modeling and optical absorption (OA) measurements prove that the NPs form localized surface plasmons (LSP) structure with a broad OA band peaked near 440-460 nm and the fringe electric field extending down to about 10 nm into the GaN layer. The presence of this NP LSP electrical field increases the photoluminescence (PL) intensity of the MQW structure by about 70% and markedly decreases the time-resolved PL (TRPL) relaxation time due to the strong coupling of MQW emission to the LSP mode.

Highlights

Surface plasmons (SP) are of great interest to many scientists in various research fields due to the extremely strong light concentration in sub-wavelength-thick metallic structures [1, 2]
Modeling and optical absorption (OA) measurements prove that the NPs form localized surface plasmons (LSP) structure with a broad OA band peaked near 440−460 nm and the fringe electric field extending down to about 10 nm into the GaN layer
We believe the Ag/SiO2 core-shell LSPenhanced MQW structure to be one of the possible paths to high efficiency stable LED structures

Summary

Introduction

Surface plasmons (SP) are of great interest to many scientists in various research fields due to the extremely strong light concentration in sub-wavelength-thick metallic structures [1, 2]. In conventional LEDs, the emission efficiency depends on the optical extraction efficiency and internal quantum efficiency The latter is limited by several factors, such as a high threading dislocation density contributing to the high density of nonradiative recombination centers and the quantum confined Stark effect due to strong polarization fields in GaN-based quantum wells. The former is severely handicapped by the high refractive index of GaN leading to a low angle of total internal reflection and a low portion of light that can be extracted from the active region of LEDs [13]

Methods

Results

Conclusion