The effect of the last quantum barrier on the internal quantum efficiency of InGaN-light emitting diode

2008 ◽  
Vol 93 (10) ◽  
pp. 101112 ◽  
Author(s):  
Eun-Hyun Park ◽  
Jin Jang ◽  
Shalini Gupta ◽  
Ian Ferguson ◽  
Soo-Kun Jeon ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Light Emitting

scholarly journals Internal quantum efficiency improvement of InGaN/GaN multiple quantum well green light-emitting diodes

2016 ◽  
Vol 24 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Q. Zhou ◽  
M. Xu ◽  
H. Wang
Keyword(s):  
Quantum Well ◽  
Quantum Efficiency ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Multiple Quantum Well ◽  
Visible Light Communication ◽  
Multiple Quantum ◽  
Internal Electric Field ◽  
Light Emitting ◽  
Green Led

In recent years, GaN-based light-emitting diode (LED) has been widely used in various applications, such as RGB lighting system, full-colour display and visible-light communication. However, the internal quantum efficiency (IQE) of green LEDs is significantly lower than that of other visible spectrum LED. This phenomenon is called “green gap”. This paper briefly describes the physical mechanism of the low IQE for InGaN/GaN multiple quantum well (MQW) green LED at first. The IQE of green LED is limited by the defects and the internal electric field in MQW. Subsequently, we discuss the recent progress in improving the IQE of green LED in detail. These strategies can be divided into two categories. Some of these methods were proposed to enhance crystal quality of InGaN/GaN MQW with high In composition and low density of defects by modifying the growth conditions. Other methods focused on increasing electron-hole wave function overlap by eliminating the polarization effect.

scholarly journals Internal Quantum Efficiency of UV μLED Chips

2019 ◽  
Vol 9 (3) ◽  
pp. 450
Author(s):  
Yoshihiko Muramoto ◽  
Masahiro Kimura ◽  
Akihiro Kondo
Keyword(s):  
Quantum Efficiency ◽  
Mass Production ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Luminous Efficiency ◽  
Crystal Defects ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Ultraviolet Range ◽  
Uv Leds

Micro light emitting diode (μLED) displays have been in development since 2017, aimed for application in 2020. However, when using three-color, i.e., red, blue, and green LEDs, or blue LEDs that excite red and green phosphors, many challenges arise in mass production, cost, and quality. Our group has devised an ultraviolet (UV)-excited red, green, and blue (RGB) display that excites red, green, and blue phosphors using UV-LEDs. This paper studies how the composition and crystal defects of a light-emitting layer affect the luminous efficiency of a UV μLED chip from the perspective of internal quantum efficiency (IQE). It was confirmed that the luminous efficiency improves by making the LED chips in the near ultraviolet range μ-size. The UV μLED chip emitting at 385 nm exhibited a more linear output than a 400-nm purple μLED chip.

scholarly journals High Temperature and Power Dependent Photoluminescence Analysis on Commercial Lighting and Display LED Materials for Future Power Electronic Modules

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Abbas Sabbar ◽  
Syam Madhusoodhanan ◽  
Sattar Al-Kabi ◽  
Binzhong Dong ◽  
Jiangbo Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Quantum Wells ◽  
Quantum Efficiency ◽  
Spontaneous Emission ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Multiple Quantum ◽  
Power Electronic ◽  
Light Emitting ◽  
Red Led

AbstractCommercial light emitting diode (LED) materials - blue (i.e., InGaN/GaN multiple quantum wells (MQWs) for display and lighting), green (i.e., InGaN/GaN MQWs for display), and red (i.e., Al0.05Ga0.45In0.5P/Al0.4Ga0.1In0.5P for display) are evaluated in range of temperature (77–800) K for future applications in high density power electronic modules. The spontaneous emission quantum efficiency (QE) of blue, green, and red LED materials with different wavelengths was calculated using photoluminescence (PL) spectroscopy. The spontaneous emission QE was obtained based on a known model so-called the ABC model. This model has been recently used extensively to calculate the internal quantum efficiency and its droop in the III-nitride LED. At 800 K, the spontaneous emission quantum efficiencies are around 40% for blue for lighting and blue for display LED materials, and it is about 44.5% for green for display LED materials. The spontaneous emission QE is approximately 30% for red for display LED material at 800 K. The advance reported in this paper evidences the possibility of improving high temperature optocouplers with an operating temperature of 500 K and above.

scholarly journals Enhanced Internal Quantum Efficiency of Bandgap-Engineered Green W-Shaped Quantum Well Light-Emitting Diode

2018 ◽  
Vol 9 (1) ◽  
pp. 77 ◽  
Author(s):  
Muhammad Usman ◽  
Urooj Mushtaq ◽  
Dong-Guang Zheng ◽  
Dong-Pyo Han ◽  
Muhammad Rafiq ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Efficiency ◽  
Recombination Rate ◽  
Auger Recombination ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Green Light ◽  
Light Emitting ◽  
Hole Confinement ◽  
Electromechanical Field

To improve the internal quantum efficiency of green light-emitting diodes, we present the numerical design and analysis of bandgap-engineered W-shaped quantum well. The numerical results suggest significant improvement in the internal quantum efficiency of the proposed W-LED. The improvement is associated with significantly improved hole confinement due to the localization of indium in the active region, leading to improved radiative recombination rate. In addition, the proposed device shows reduced defect-assisted Shockley-Read-Hall (SRH) recombination rate as well as Auger recombination rate. Moreover, the efficiency rolloff in the proposed device is associated with increased built-in electromechanical field.

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