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(Invited) Deep Ultraviolet Light Emitting Diodes: Physics, Performance, and Applications
(Invited) Deep Ultraviolet Light Emitting Diodes: Physics, Performance, and Applications
Monday, May 12, 2014: 13:30
Manatee, Ground Level (Hilton Orlando Bonnet Creek)
Materials quality is the one of the key factors determining the Deep UV LED performance. It could be dramatically improved by using novel MEMOCVD® technique [1] using overlapping precursor pulses, optimized precursor waveforms and lower growth temperatures compared to the conventional MOCVD growth. Another key factor is the Deep UV LED design. Using very narrow quantum wells (QWs), we achieved an improved overlap between electron and hole wave functions and increased the Internal Quantum Efficiency. We also used “the energy tub” [2] to increase the electron capture into the QWs and eliminate or reduce the “blocking layer.” These approaches and a novel transparent and reflecting top contact have led to a high internal quantum efficiency, high power output and high external quantum efficiency of our Deep UV LEDs. Research is now under way to use these devices for improving quality and extending storage time of fruits and vegetables.[3] Other applications include water and air purification, sterilization, biological threat identification, applications in medicine, biology, industrial processes, defense, and homeland security. Deep UV LEDs have a potential of replacing conventional ultraviolet Hg vapor, Xenon and Deuterium lamps that are bulky, contain mercury, produce ozone, require high voltages, slow to turn on, and have a limited set of available wavelengths. DUV LEDs will also enable new applications that were not even possible with conventional deep UV technology.
[1] R. Gaska, J. Zhang, and M. Shur “Nitride-based light emitting heterostructure”, US Patent 7,326,963, Feb. (2008)
[2] Q. Fareed, R. Gaska and M. S. Shur, Methods of Growing Nitride-Based Film Using Varying Pulses, US patent 7192849, March 20 (2007)
[3] M. Shur and S. Britz, Fluorescent-based ultraviolet illumination, United States Patent Application Publication, US 2011/0147617, June 23 (2011), US patent 8,384,047, Feb. 26 (2013)