scholarly journals Effects of Different InGaN/GaN Electron Emission Layers/Interlayers on Performance of a UV-A LED

2020 ◽  
Vol 10 (4) ◽  
pp. 1514
Author(s):  
Dohyun Kim ◽  
Keun Song ◽  
UiJin Jung ◽  
Subin Kim ◽  
Dong Shin ◽  
...  
Keyword(s):  
Barrier Layer ◽  
Light Emitting Diode ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Growth Time ◽  
Multiple Quantum ◽  
Lower Growth ◽  
Light Emitting ◽  
Injection Use ◽  
Metal Organic

In this study, we investigated the effects of InGaN/GaN-based interlayer (IL) and electron emitting layer (EEL) consisting of a GaN barrier layer grown with different metal-organic (MO) precursors of gallium (Ga), which were grown underneath the active layer. The growth behavior of GaN with triethyl Ga (TEGa) showed an increasing growth time due to a lower growth rate compared with GaN grown with trimethyl Ga (TMGa), resulting in the formation of columnar domains and grain boundary with reduced defect. UV-A light emitting diode (LED) chips with three types of ILs and EELs, grown with different MO sources, were fabricated and evaluated by light output power (LOP) measurements. The LOP intensity of UVLED-III with the GaN barrier layer-based IL and EEL grown by TEGa was enhanced by 1.5 times compared to that of the IL and EEL grown with TMGa at 300 mA current injection. Use of the GaN barrier layer in ILs and EELs grown by TEGa improved the crystal quality of the post grown InGaN/GaN multiple quantum well, which reduces leakage current. Therefore, for the UV-A LED with ILs and EELs grown with TEGa MO precursors, electrical and optical properties were improved significantly.

Low-Temperature Operation of Green, Blue and UV InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes

2003 ◽  
Vol 764 ◽  
Author(s):  
X. A. Cao ◽  
S. F. LeBoeuf ◽  
J. L. Garrett ◽  
A. Ebong ◽  
L. B. Rowland ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Localized States ◽  
Multiple Quantum ◽  
Nonradiative Recombination ◽  
Light Emitting ◽  
Temperature Range ◽  
Green Leds

Absract:Temperature-dependent electroluminescence (EL) of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with peak emission energies ranging from 2.3 eV (green) to 3.3 eV (UV) has been studied over a wide temperature range (5-300 K). As the temperature is decreased from 300 K to 150 K, the EL intensity increases in all devices due to reduced nonradiative recombination and improved carrier confinement. However, LED operation at lower temperatures (150-5 K) is a strong function of In ratio in the active layer. For the green LEDs, emission intensity increases monotonically in the whole temperature range, while for the blue and UV LEDs, a remarkable decrease of the light output was observed, accompanied by a large redshift of the peak energy. The discrepancy can be attributed to various amounts of localization states caused by In composition fluctuation in the QW active regions. Based on a rate equation analysis, we find that the densities of the localized states in the green LEDs are more than two orders of magnitude higher than that in the UV LED. The large number of localized states in the green LEDs are crucial to maintain high-efficiency carrier capture at low temperatures.

scholarly journals Improved Performance of GaN-Based Light-Emitting Diodes Grown on Si (111) Substrates with NH3 Growth Interruption

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 399
Author(s):  
Sang-Jo Kim ◽  
Semi Oh ◽  
Kwang-Jae Lee ◽  
Sohyeon Kim ◽  
Kyoung-Kook Kim
Keyword(s):  
Buffer Layer ◽  
Light Emitting Diodes ◽  
Defect Density ◽  
Strain Relaxation ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Growth Interruption ◽  
Aln Buffer

We demonstrate the highly efficient, GaN-based, multiple-quantum-well light-emitting diodes (LEDs) grown on Si (111) substrates embedded with the AlN buffer layer using NH3 growth interruption. Analysis of the materials by the X-ray diffraction omega scan and transmission electron microscopy revealed a remarkable improvement in the crystalline quality of the GaN layer with the AlN buffer layer using NH3 growth interruption. This improvement originated from the decreased dislocation densities and coalescence-related defects of the GaN layer that arose from the increased Al migration time. The photoluminescence peak positions and Raman spectra indicate that the internal tensile strain of the GaN layer is effectively relaxed without generating cracks. The LEDs embedded with an AlN buffer layer using NH3 growth interruption at 300 mA exhibited 40.9% higher light output power than that of the reference LED embedded with the AlN buffer layer without NH3 growth interruption. These high performances are attributed to an increased radiative recombination rate owing to the low defect density and strain relaxation in the GaN epilayer.

Red Emission of InGaN/GaN Multiple-Quantum-Well Light-Emitting Diode Structures with Indium-Rich Clusters

2018 ◽  
Vol 215 (23) ◽  
pp. 1800455 ◽  
Author(s):  
Yulin Meng ◽  
Lianshan Wang ◽  
Guijuan Zhao ◽  
Fangzheng Li ◽  
Huijie Li ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diode ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Red Emission ◽  
Light Emitting

scholarly journals Multi-Domain Modelling of LEDs for Supporting Virtual Prototyping of Luminaires

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1909 ◽  
Author(s):  
András Poppe ◽  
Gábor Farkas ◽  
Lajos Gaál ◽  
Gusztáv Hantos ◽  
János Hegedüs ◽  
...  
Keyword(s):  
Thermal Environment ◽  
Light Emitting Diode ◽  
Virtual Prototyping ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Operating Conditions ◽  
Domain Model ◽  
Multiple Quantum ◽  
Seamless Integration ◽  
Output Characteristics

This paper presents our approaches to chip level multi-domain LED (light emitting diode) modelling, targeting luminaire design in the Industry 4.0 era, to support virtual prototyping of LED luminaires through luminaire level multi-domain simulations. The primary goal of such virtual prototypes is to predict the light output characteristics of LED luminaires under different operating conditions. The key component in such digital twins of a luminaire is an appropriate multi-domain model for packaged LED devices that captures the electrical, thermal, and light output characteristics and their mutual dependence simultaneously and consistently. We developed two such models with this goal in mind that are presented in detail in this paper. The first model is a semi analytical, quasi black-box model that can be implemented on the basis of the built-in diode models of spice-like circuit simulators and a few added controlled sources. Our second presented model is derived from the physics of the operation of today’s power LEDs realized with multiple quantum well heterojunction structures. Both models have been implemented in the form of visual basic macros as well as circuit models suitable for usual spice circuit simulators. The primary test bench for the two circuit models was an LTspice simulation environment. Then, to support the design of different demonstrator luminaires of the Delphi4LED project, a spreadsheet application was developed, which ensured seamless integration of the two models with additional models representing the LED chips’ thermal environment in a luminaire. The usability of our proposed models is demonstrated by real design case studies during which simulated light output characteristics (such as hot lumens) were confirmed by luminaire level physical tests.

Sign in / Sign up

Export Citation Format

Share Document