InGaN/GaN multilayer quantum dots yellow-green light-emitting diode with optimized GaN barriers

Wenbin Lv,Jiaxing Wang,Yi Luo,Lai Wang,Zhibiao Hao

doi:10.1186/1556-276x-7-617

Abstract

InGaN/GaN multilayer quantum dot (QD) structure is a potential type of active regions for yellow-green light-emitting diodes (LEDs). The surface morphologies and crystalline quality of GaN barriers are critical to the uniformity of InGaN QD layers. While GaN barriers were grown in multi-QD layers, we used improved growth parameters by increasing the growth temperature and switching the carrier gas from N2 to H2 in the metal organic vapor phase epitaxy. As a result, a 10-layer InGaN/GaN QD LED is demonstrated successfully. The transmission electron microscopy image shows the uniform multilayer InGaN QDs clearly. As the injection current increases from 5 to 50 mA, the electroluminescence peak wavelength shifts from 574 to 537 nm.

Highlights

In recent years, white light-emitting diodes (LEDs) have attracted much attention for applications in general lighting and liquid crystal display back-lighting [1,2]
In the spectral range of green gap, the efficiency of yellow-green LEDs decreases dramatically compared to that of short-wavelength green LEDs [7]. This is attributed to the low internal quantum efficiency (IQE) of InGaN/GaN multi-quantum wells (MQWs) with high indium composition
The reactor temperature was decreased to 650°C, and N2 was used as the carrier gas in place of H2 for InGaN quantum dot (QD) growth

Summary

Introduction

White light-emitting diodes (LEDs) have attracted much attention for applications in general lighting and liquid crystal display back-lighting [1,2]. The performance of RGB white LEDs fails to meet expectation due to the well-known ‘green gap’ [4,5,6]. In the spectral range of green gap, the efficiency of yellow-green LEDs decreases dramatically compared to that of short-wavelength green LEDs [7]. This is attributed to the low internal quantum efficiency (IQE) of InGaN/GaN multi-quantum wells (MQWs) with high indium composition.

Methods

Results

Conclusion