Deep Ultraviolet Light Emitting Diodes with Emission below 300 nm

2005 ◽  
Vol 892 ◽  
Author(s):  
M. Asif Khan
Keyword(s):  
Multiple Quantum Well ◽  
Structure Design ◽  
Multiple Quantum ◽  
Device Structure ◽  
Light Emitting ◽  
Uv Led ◽  
Excellent Research ◽  
Deep Uv ◽  
P Type ◽  
Uv Leds

AbstractIn this paper we will describe the problems in growth and fabrication of deep UV LED devices and the approaches that we have used to grow AlGaN-based multiple quantum well deep UV LED structures and to overcome issues of doping efficiency, cracking, and slow growth rates both for the n- and the p-type layers of the device structures. Several innovations in structure growth, device structure design and fabrication and packaging have led to the fabrication of devices with emission from 250-300 nm and cw-milliwatt powers at pump currents of only 20 mA (Vf ≤ 6 V). Record wall plug efficiencies above 1.5 % are now achievable for devices with emission at 280 nm. Thermal management and a proper device design are not only key factors in achieving these record performance numbers but are also crucial to device reliability. We will also discuss some of our initial research to clarify the factors influencing the lifetime of the deep UV LEDs. In addition to our own work, we will review the results from the excellent research carried out at several other laboratories worldwide.

Theoretical Study on the Optoelectronic Properties of Al1-xGaxN-Based Deep UV LEDs with Single and Multiple Quantum Well Heterostructures

2021 ◽  
Author(s):  
Galih Ramadana Suwito ◽  
Ya-Hsuan Shih ◽  
Sung-Wen Huang Chen ◽  
Zi-Hui Zhang ◽  
Hao-Chung Kuo
Keyword(s):  
Quantum Well ◽  
Theoretical Study ◽  
Multiple Quantum Well ◽  
Optoelectronic Properties ◽  
Multiple Quantum ◽  
Deep Uv ◽  
Uv Leds

MBE-Grown CdZnO/ZnO Multiple Quantum-Well Light-Emitting Diode on MOCVD-Grown p-Type GaN

2012 ◽  
Vol 24 (11) ◽  
pp. 909-911 ◽  
Author(s):  
Shao-Ying Ting ◽  
Horng-Shyang Chen ◽  
Wen-Ming Chang ◽  
Jeng-Jie Huang ◽  
Che-Hao Liao ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diode ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Light Emitting ◽  
P Type

Origins and suppressions of parasitic emissions in ultraviolet light-emitting diode structures

2010 ◽  
Vol 25 (6) ◽  
pp. 1037-1040 ◽  
Author(s):  
Weihuang Yang ◽  
Shuping Li ◽  
Hangyang Chen ◽  
Dayi Liu ◽  
Junyong Kang
Keyword(s):  
Quantum Wells ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Force Microscopy ◽  
Uv Led ◽  
Hole Blocking Layer ◽  
To Come ◽  
P Type

The AlGaN-based ultraviolet (UV) light-emitting diode (LED) structures with AlN as buffer were grown on sapphire substrate by metalorganic vapor-phase epitaxy (MOVPE). A series of cathodoluminescence (CL) spectra were measured from the cross section of the UV-LED structure using point-by-point sampling to investigate the origins of the broad parasitic emissions between 300 and 400 nm, and they were found to come from the n-type AlGaN and AlN layers rather than p-type AlGaN. The parasitic emissions were effectively suppressed by adding an n-type AlN as the hole-blocking layer. Electroluminescence (EL) and atomic force microscopy (AFM) measurements have revealed that the interface abruptness and crystalline quality of the UV-LED structure are essential for the achievement of the EL emissions from the multiple quantum wells (MQWs).

Thermal Characterization of Discrete Device Layers in AlxGa1−xN Based Ultraviolet Light Emitting Diodes

2012 ◽  
Author(s):  
Shweta Natarajan ◽  
Bobby G. Watkins ◽  
Vinod Adivarahan ◽  
Asif Khan ◽  
Samuel Graham
Keyword(s):  
Raman Spectroscopy ◽  
Temperature Rise ◽  
Multiple Quantum Well ◽  
Thermal Characterization ◽  
Optical Methods ◽  
Multiple Quantum ◽  
Device Structure ◽  
Light Emitting ◽  
Discrete Device ◽  
Device Lifetime

The temperature rise in LEDs is an important parameter that must be determined for both thermal management and device lifetime/reliability assessment. Commonly used indirect methods of measuring the device temperature either estimate the multiple quantum well (MQW) temperature based on measuring temperature dependent device characteristics (e.g., forward voltage and electroluminescence methods), or they measure the average temperature across the device structure using optical methods such as infrared (IR) thermography and thermoreflectance. However, none give true insight into the vertical distribution of temperature in these structures. In this study, Raman spectroscopy is applied for the first time to operating UV LEDs to give the temperature rise in discrete layers within the LED device structure, going from the growth substrate to layers adjacent to theMQWs. Comparisons are made with IR themography to contrast with this depth sensitive measurement technique. It was observed that the peak temperatures in the device were much higher than the temperatures indicated by IR while the averaged temperatures through the structure compared favorably. Additional comparisons to electroluminescence measurements were also made which compared favorably with the peak temperatures found by Raman Spectroscopy.

Ultraviolet light emitting diodes using non-polar A-plane AlGaN multiple quantum wells

2006 ◽  
Vol 955 ◽  
Author(s):  
Ramya Chandrasekaran ◽  
Anirban Bhattacharyya ◽  
Ryan France ◽  
Christos Thomidis ◽  
Adrian Williams ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Current Voltage ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes ◽  
Electro Luminescence

ABSTRACTIn this paper, we report the growth and fabrication of non-polar A-plane AlGaN multiple quantum well based ultraviolet light emitting diodes (UV-LEDs). The LEDs were grown on R-plane sapphire substrates using molecular beam epitaxy (MBE). The Current-voltage characteristics of the fabricated devices demonstrated rectifying behavior with a series resistance of 38 ohms. An electro-luminescence emission at 338 nm was obtained.

scholarly journals Using InGaN/GaN Multiple Quantum well Green light-Emitting Diodes as a Promising Replacement of Conventional light Sources

2019 ◽  
Vol 9 (1) ◽  
pp. 5205-5209
Keyword(s):  
Multiple Quantum Well ◽  
Three Dimensional ◽  
Green Light ◽  
Light Sources ◽  
Multiple Quantum ◽  
Internal Electric Field ◽  
Light Emitting ◽  
Green Led ◽  
P Type ◽  
The Impact

In this particular paper we increase a graded indium composition p type InGaN (p InGaN) conduction level to supplant the p type AlGaN electron blocking level & a p GaN level to update the mild yield intensity of a GaN based green light transmitting diode (LED). The indium structure of the p InGaN coating reduced from 10.4 % to zero % across the development heading. A tale configuration is proposed for n-electrode with openings to be connected in Thin-GaN light-transmitting diodes (LEDs). The impact of the n-electrode with gaps on the thermal and electrical qualities of a Thin-GaN LED chip is researched utilizing a three-dimensional numerical simulation The IQE of green LED is restricted by the deformities and the internal electric field in MQW. Thusly, we talk about the ongoing advancement in improving the IQE of green LED in detail. These techniques can be partitioned into two classes. A portion of these techniques were proposed to upgrade precious stone nature of InGaN/GaN MQW with high. In composition and low thickness of deformities by adjusting the development conditions. Different strategies concentrated on expanding electron−hole wave function cover by dispensing with the polarization impact.

New UV Light Emitter Based on AlGaN Heterostructures with Graded Electron and Hole Injectors

2002 ◽  
Vol 743 ◽  
Author(s):  
M.A.L. Johnson ◽  
J.P. Long ◽  
J. F. Schetzina
Keyword(s):  
Aluminum Gallium Nitride ◽  
Light Emission ◽  
Uv Light ◽  
Multiple Quantum Well ◽  
Forward Bias ◽  
Hole Injection ◽  
Bandgap Energy ◽  
Multiple Quantum ◽  
Device Structure ◽  
Light Emitting

ABSTRACTNew ultraviolet (UV) light emitting device structures address the problems of small carrier concentrations and large band-offsets in wide bandgap Aluminum Gallium Nitride (AlGaN) heterostructures through the use of graded epilayers for electron and hole injection. For light emission at 280–290 nm, a multiple-quantum-well separate confinement heterostructure (MQWSCH) employs a graded AlGaN structure for the injection of majority carriers from the metal-semiconductor contact layers into the spacecharge region of the pn-junction with a higher bandgap energy. Sample LED mesa devices were fabricated and have shown light emission of 289 nm under a forward bias of 12V (20mA). These results provide a ‘proof-of-concept’ for this new graded device structure which can be employed for the development of both UV-LEDs and laser diodes.

scholarly journals Enhanced hole transport in InGaN/GaN multiple quantum well light-emitting diodes with a p-type doped quantum barrier

2013 ◽  
Vol 38 (2) ◽  
pp. 202 ◽  
Author(s):  
Yun Ji ◽  
Zi-Hui Zhang ◽  
Swee Tiam Tan ◽  
Zhen Gang Ju ◽  
Zabu Kyaw ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Hole Transport ◽  
Multiple Quantum ◽  
Light Emitting ◽  
P Type
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