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.

Enhancement of light-emission efficiency of ultraviolet InGaN/GaN multiple quantum well light emitting diode with InGaN underlying layer

2012 ◽  
Vol 108 (4) ◽  
pp. 771-776 ◽  
Author(s):  
Lei Liu ◽  
Lei Wang ◽  
Cimang Lu ◽  
Ding Li ◽  
Ningyang Liu ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Emission Efficiency

Simulation study of blue InGaN multiple quantum well light-emitting diodes with different hole injection layers

2012 ◽  
Vol 21 (6) ◽  
pp. 068506 ◽  
Author(s):  
Le-Juan Wu ◽  
Shu-Ti Li ◽  
Chao Liu ◽  
Hai-Long Wang ◽  
Tai-Ping Lu ◽  
...  
Keyword(s):  
Quantum Well ◽  
Simulation Study ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Hole Injection ◽  
Multiple Quantum ◽  
Light Emitting

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.

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.

Precise Electrical Characterization of LEDs with Wide-Band Material

2013 ◽  
Vol 411-414 ◽  
pp. 1654-1659
Author(s):  
Yang Li ◽  
Lie Feng Feng ◽  
Cun Da Wang ◽  
Qiong Yong Xing
Keyword(s):  
Multiple Quantum Well ◽  
Forward Bias ◽  
Low Frequency ◽  
Electrical Characterization ◽  
Wide Band ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Current Voltage ◽  
Red Led

The accurate electrical properties of semiconductor GaN based blue Light-Emitting Diodes (LED) with Multiple-Quantum Well (MQW) structure and GaAsP based red LED, were measured by single Capacitance-Voltage (C-V) method and single Current-Voltage (I-V) method at large forward bias. After comparing the experimental results, we found that the apparent capacitance Cp of GaN based blue LED and GaAsP based red LED measured by C-V method display obviously negative value at large forward bias and low frequency, which is in conflict with the well known Shockley's p-n junction theory and model. Besides, the precise Characterization of apparent capacitance Cp and apparent conductance Gp is obtained.

Differential Carrier Lifetime in AlGaN Based Multiple Quantum Well Deep UV Light Emitting Diodes at 325 nm

2002 ◽  
Vol 41 (Part 2, No. 10B) ◽  
pp. L1146-L1148 ◽  
Author(s):  
Maxim Shatalov ◽  
Ashay Chitnis ◽  
Alexey Koudymov ◽  
Jianping Zhang ◽  
Vinod Adivarahan ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Carrier Lifetime ◽  
Uv Light ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Deep Uv
Sign in / Sign up

Export Citation Format

Share Document