Solid State Lighting & Energy Center

Indirect Auger Figure

	Special Substrate Helps LEDs Shine Brighter Without Losing Efficiency http://www.dailytech.com/Special+Substrate+Helps+LEDs+Shine+Brighter+Without+Losing+Efficiency/article24654.htm May 10, 2012 University of California - Santa Barbara researchers have found a way to make blue and green light-emitting diodes (LEDs) http://www.dailytech.com/Fords+New+Fusion+Ditches+Interior+Incandescent+Bulbs+Goes+All+LED/article24080.htm give off more light without the barrier of a second field. Yuji Zhao, study leader and materials scientist at the University of California - Santa Barbara, has figured out a way to make LED lights useful for more than just small objects. (photo source: ledlightswarehouse.com)
	Nitrides Seminars 10 May 2012 Prof. Dr. Friedhelm Bechstedt from Friedrich-Schiller Universitaet Jena, Germany, was a guest speaker at the May 10th Nitrides Seminar and gave a lecture on "InGaN and InAlN alloys from first principles." Prof. Dr. Bechstedt is pictured here with Professor Chris Van de Walle.
	Conquering LED Efficiency Droop: Overcoming Mysterious Phenomenon Could Lead to Affordable LED Lighting 30 April 2012 &qout;We believe this technology could be a big breakthrough and has the potential to change the future of lighting,&qout; says Yuji Zhao, a graduate student at the Solid State Lighting and Energy Center at the University of California Santa Barbara (UCSB) and one of the lead researchers on the team. Story Links: LaserFocus World ScienceDaily Product Design & Development
	AlGaN buffers on semipolar GaN offer new route to UV LDs 30 April 2012 University of California Santa Barbara (UCSB) has developed ultraviolet (UV) laser diodes (LDs) based on semipolar aluminum gallium nitride (AlGaN) buffer layers [Daniel A. Haeger et al, Appl. Phys. Lett., vol100, p161107, 2012]. The aim was to provide an alternative route to UV LDs compared with those grown on AlN or sapphire substrates. Full Story
	Aixtron, ASM, NTU, Philips Lumileds and University of California Santa Barbara Share Insights into the LED Technologies at SEMICON Singapore LED provide environmental protection and energy savings. Posted on 30 April 2012 by Augustine Quek http://www.ceasiamag.com/article/aixtron-asm-ntu-philips-lumileds-and-univer sity-of-california-santa-barbara-share-insights-into-the-led-technologies-at -semicon-singapore/8462 As white solid-state lighting (SSL) has become the main stream, one of the invited speakers, Prof. Steven Denbaars, Professor of Materials and Co-Director of the Solid-State Lighting Center, University of California Santa Barbara, noted: The U.S. Department of Energy estimates that in 2030 the energy savings from LED lighting in the U.S. alone would amount to over $250 billion in energy savings, which is equivalent to 50 Gigawatt size power plants. Further improvements in materials quality and cost reduction are necessary for wide-spread adoption of LEDs for lighting. Besides, the SSL has the potential to achieve 85% energy efficiency.
	Magnesium puzzle solving in nitride semiconductors 24 April 2012 University of California Santa Barbara (UCSB) scientists have reported density functional calculations that shed light on the puzzling behavior of magnesium (Mg) as p-type (acceptor) dopant in nitride semiconductor materials involving the elements gallium (Ga), aluminum (Al) and indium (In) [John L. Lyons et al, Phys. Rev. Lett., vol108, p156403, 2012]. Link: http://www.semiconductor-today.com/news_items/2012/APRIL/UCSB_240412.html
	Shedding light on the p-type doping of GaN 16 April 2012 UCSB theorists have revealed that magnesium in GaN is not a typical shallow acceptor John Lyons and Anderson Janotti, working in Chris Van de Walle’s Computational Materials Group at the University of California, Santa Barbara (UCSB) have now unravelled this behaviour using state-of-the-art first-principles methods. They found that the magnesium acceptor exhibits dual character. Full Story
	Nitrides Seminars 13 April 2012 Dr. Gregor Koblmüller from the Walter Schottky Institute, Technical University Munich, Germany, was a guest speaker at the April 13th Nitrides Seminar and gave a lecture on III-V Nanowire Arrays on Silicon: Growth, Material Properties and Prospects for Heterojunction Devices. Dr. Koblmüller is pictured here with Professor Chris Van de Walle.
	University of California, Santa Barbara Brings Cool to School UC Santa Barbara Honored With Membership in Southern California Edison's Cool Planet Program 22 March 2012 UCSB houses the Solid State Lighting & Energy Center and the Institute for Energy Efficiency, devoted to addressing challenges and breakthroughs in the energy sector. The Solid State Lighting & Energy Center develops new semiconductor based technologies for energy efficient lighting, solar energy conversion, and power electronics. Economic policies and technologies to promote energy efficiency are the focus at the Institute for Energy Efficiency. http://www.globenewswire.com/ http://finance.yahoo.com/news/university-california-santa-barbara-brings-211415960.html/
	UCSB listed as CS Industry Awards 2012 R&D nominee 28 February 2012 The CS Industry Awards will recognise the success and development along the entire value chain of the Compound Semiconductor industry from research to completed device. The Awards will focus on the people, processes and products that drive the industry forward. Technical expertise alone will not ensure a successful company, so Compound Semiconductor has created the CS Industry Awards to recognise the vital individuals and companies that enable a company to achieve success in a competitive global market. Award recipients will be announced on March 12th at the CS Europe Conference in Frankfut, Germany. Full Story
	February 20, 2012 Engineers Take Aim at a Barrier in LED Technology \|BY JOHN MARKOFF http://topics.nytimes.com/top/reference/timestopics/people/m/john_markoff/index.html?inline=nyt-per The high brightness blue LED, the kind used today but too expensive for extensive use, was invented in 1993 by Shuji Nakamura, a Japanese physicist who is one of the founders of Soraa. This month, the firm claimed a breakthrough in circumventing LED droop. However, it is keeping the details of it's new technology proprietary. Despite Soraa's secrecy, last April a group of researchers at the University of California, Santa Barbara, where Dr. Nakamura took a faculty position after leaving Japan in 1999 and where two of his co-founders, Steve DenBaars and Jim Speck, also teach, published a research report indicating that they had found evidence that LED droop could be explained by a process known as Auger recombination. http://www.nytimes.com/2012/02/21/science/engineers-take-aim-at-efficiency-barrier-in-led-technology.html?_r=1
	Many uses of LED's 6 Febuary 2012 Festival Brings Light To The Depth Of Winter - Yahoo! Travel Story
	Steven DenBaars elected as a new member of the National Academy of Engineering 9 Febuary 2012 Steven P. DenBaars, the SSLEC Executive Director and the Materials Department's Mitsubishi Chemical Professor in Solid State Lighting and Displays,was elected as a new member of the National Academy of Engineering. He was recognized for contributions to gallium nitride-based materials and devices for solid state lighting and displays. UCSB Press Release NAE Story SPIE (Society of Photographic Instrumentation Engineers) Story
	The Quest for Cheaper, Better Lights 7 Febuary 2012 Soraa, the world’s leading developer of GaN on GaNTM – gallium nitride on gallium nitride – solid-state lighting technology, today announced the launch of its flagship product, the Soraa LED MR16 lamp. The new product is the first LED lamp to provide superior performance to a traditional halogen MR16. It is also the first LED lamp to provide halogen-equivalent brightness without requiring a mechanical fan and payback within months, not years. The Soraa LED MR16 lamp based on GaN on GaNTM technology represents a revolutionary breakthrough in lighting technology: LED 2.0. Founded by Shuji Nakamura, Steve DenBaars, and James Speck, Soraa leverages decades of expertise from the father of modern LED lighting, Shuji Nakamura, and preeminent solid-state lighting experts from the University of California, Santa Barbara. Full Story Wall Street Journal Video
	Carpinteria Switches to LED Street Lighting 26 January 2012 To save on energy bills, cities around the nation are setting their sights on a familiar target - high-pressure sodium vapor street lights and replacing them with light-emitting diodes (LEDs). Because of their daylight-like brightness, LED lighting promotes neighborhood safety at night while trimming the energy use and maintenance costs of local governments converting from traditional lighting. Full Story
	Chris Van de Walle one of three UCSB Professors Elected as IEEE Fellows 19 January 2012 Three faculty members with the UCSB College of Engineering have been recognized by the world's largest technology professional association for their research contributions. Chris Van de Walle, professor of Materials, was acknowledged for his contributions to the theory of interfaces, doping and defects in semiconductors. Van de Walle is Director of the Computational Materials Group and an affiliated faculty member with the California NanoSystems Institute, Institute for Energy Efficiency, Solid State Lighting and Energy Center, Center for Energy Efficient Materials, and Interdisciplinary Center for Wide Bandgap Semiconductors at UCSB. Before joining the UCSB Materials Department in 2004, Chris Van de Walle was a Principal Scientist in the Electronic Materials Laboratory at the Xerox Palo Alto Research Center. Van de Walle received a PhD in Electrical Engineering from Stanford University. Full Story
	UCSB Researchers Uncover Transparency Limits on Transparent Conducting Oxides 18 January 2012 Computational Materials researchers at UC Santa Barbara use cutting-edge calculations to determine fundamental optical transparency limits in conducting oxide material tin oxide "Every bit of light that gets absorbed reduces the efficiency of a solar cell or LED", remarked Chris Van de Walle. "Understanding what causes the absorption is essential for engineering improved materials to be used in more efficient devices." Van de Walle's Computational Materials Group is affiliated with the College of Engineering at UCSB. Their research explores semiconducting binary oxides, nitride semiconductors, novel channel materials and dielectrics, materials for quantum computing, photochemical hydrogen generation, and metallic nanoparticles. Learn more about Computational Materials research at www.mrl.ucsb.edu/~vandewalle. Full story: here and here.
	SSLEC receives endowment chair from Seoul Optodevice Company Ltd. 11 January 2012 The Seoul Optodevice Company, Ltd., a partner of the Solid State Lighting & Energy Center since March 2010, has made a special endowment to the center. This endowment will support a faculty member conducting fundamental material research on defect reduction in wide band-gap semiconductors, with a focus on the role of defects and crystal structure on the efficiency of solid-state lighting sources. Seoul Optodevice Company, Ltd. was established in Korea in 2002. They have continued research in LEDs to improve solid-state lighting. Through this endowment they hope to create a brighter, more energy efficient world. A special reception was held at the UCSB faculty club on January 11, 2012 honoring Mr. Chung Hoon Lee of Seoul Optodevice Company, Ltd. For the endowment. From left: SSLEC Faculty members Stephen DenBaars, and Jim Speck; Chung hoon Lee, Chancellor Yang, and Rod Alfernes, Dean of the College of Engineering.
	Shuji Nakamura receives Emmy Award 12 January 2012 Technology and Engineering Emmy Awards were presented on Jan. 12, 2012 in Las Vegas at the International Consumer Electronics Show, at the Venetian Resort Hotel & Casino. UCSB Professor Shuji Nakamura received an Emmy Award for his work on "Pioneering Development of Large-Venue, Large-Screen Direct View Color Video Displays." Program link (PDF) (Shuji Nakamura is featured on Page 8)
	LED and Gallium Nitride Tech Hub in Santa Barbara, California 6 January 2012 Blue LED inventor Shuji Nakamura draws talent and funding. Three hundred miles south of Silicon Valley, Santa Barbara is on its way to becoming a destination resort for LED activity. Full Story
	An Interview with NEA's Ravi Viswanathan 16 January 2012 Soraa www.soraa.com is a follow-on investment we made in 2011. We are very excited about that investment [and] the LED space. Soraa is a disruptive LED company. LEDs or more broadly the demand side is where we are spending a lot of [our] time. A lot of very interesting market shifts [are] happening in the LED space in the transition away from incandescent [light bulbs]. The problem with LEDs for many years has been cost. As technologies continue to improve and in the companies we¹re involved with, [LEDs] are coming down the cost curve significantly and their performance has gotten better it is going to be a really big market. Full Story Dr. Shuji Nakamura is one of the pioneers in the LED space. He started Soraa along with a couple other professors. It was a fundamental architecture difference. It¹s using a different type of architecture that increases performance and significantly reduces cost.
	http://iee.ucsb.edu/news/institute-energy-efficiency-announces-graduate-student-fellows-0 Alexander Sztein is named the 2011-12 Peter J. Frenkel Foundation Fellow by the UCSB Institute for Energy Efficiency for his work in Production and Storage Solutions Group September 15, 2011 Alexander Sztein is a candidate in the Materials Department. His dissertation is on III-Nitride Materials for Thermoelectric Applications and is being completed under the supervision of Professor Shuji Nakamura. This award is granted to advanced doctoral candidates in recognition of their outstanding research contributions to the field of energy efficiency.
	Non-polar laser diode power comparable to c-plane devices 29 November 2011 University of California Santa Barbara and Japan¹s Mitsubishi Chemical Corp have developed aluminum gallium nitride (AlGaN) cladding-free (ACF) m-plane nitride semiconductor laser diodes (LDs) with output powers comparable to state-of-the-art single-stripe emitter c-plane devices [R. M. Farrell et al, Appl. Phys. Lett., vol99, p171113, 2011].(link)
	Congratulations to Primit Parikh (UCSB Alumnus) and Umesh Mishra (Professor of ECE), founders of Transphorm, for their recognition as the Entrepreneur of the Year at the 2011 Goleta's Finest Community Awards Ceremony on November 30th. : (link)
	Nitrides Seminars University of California Santa Barbara Professor Holger Eisele from the Institut für Festkörperphysik, Technische Universität Berlin, was a guest speaker at the November 17th Nitrides Seminar and gave a lecture on Atomic and Electronic Structure of Non-polar GaN and InN Surfaces. Dr. Eisele is pictured here with Professor Speck and Erin Young.
	Japan is moving to modernise it's Universities and confront globalisation head on: (link) 27 October 2011 Rick Wallace, Tokyo correspondent Japan's Universities - assailed by claims that have failed to cope with globalisation - are moving to boost their international competitiveness and appeal. Japanese inventor and academic Shuji Nakamure, the inventor of the blue laser that integral to DVD, CD and Blu-ray players said Japanese universities still had a huge leap to make to catch up to their US counterparts.(link)
	Improving etch process control in InGaN laser diodes: (link) 28 September 2011 Mike Cooke, Technology Journalist University of California Santa Barbara (UCSB), together with Japan¹s Mitsubishi Chemical Corp, have developed an etch technique to produce more accurate ridge waveguides in nitride semiconductor laser diodes (LDs) [Robert M. Farrell et al, Appl. Phys. Express, vol4, p092105, 2011]. The technique uses an etch-stop layer of aluminum gallium nitride (AlGaN), and is made possible by UCSB¹s development last year (UCSB achieves CW operation of AlGaN-cladding-free nonpolar lasers) of nitride LDs that do not use AlGaN for the thick cladding layers needed to confine optical modes in the structure.(link)
	The LED Approaches Theoretical Maximum: (link) Questions for GE's Gary Allen Txchnologist 10/20/11 8:56 AM SPONSORED BY GE LIGHTING ISSUE 3: LIGHTING THE FUTURE
	Nitrides Seminars University of California Santa Barbara Dr. Yasufumi Fujiwara, a Professor in the Division of Materials Science and Engineering at Osaka University, was a guest speaker at the October 13th Nitrides Seminar on Current status of red light-emitting diodes with Eu-doped GaN. Dr. Fujiwara is pictured here with Professors Nakamura and DenBaars.
	Nitrides Seminars University of California Santa Barbara Dr. Yuh-Renn Wu, an Assistant Professor Institute of Photonics & Optoelectronics at the National Taiwan University, was a guest speaker at the October 20th Nitrides Seminar on Multi-dimensional Numerical Modeling Work on InGaN LEDs and Nanowire Transistors. Dr. Wu is pictured here with Professor James Speck.
	UCSB Materials Professor Shuji Nakamura to Receive Emmy Award(link) 14 September 2011 (Santa Barbara, Calif.) The National Academy of Television Arts & Sciences (NATAS) has named Shuji Nakamura, professor of materials and of electrical and computer engineering at UC Santa Barbara, among the winners of the 63rd Annual Technology & Engineering Emmy Awards. The award will be presented during the International Consumer Electronics Show in Las Vegas in January
	Seven Technical Emmy's to be awarded for HD-to-SD conversion technology (link) 10 October 2011 11:13 AM By Michael Grotticelli (link) Other Technical Emmy Awards and recipients include Samma for a system for Automated Migration of Media Assets; and Mitsubishi¹s Diamond Vision Systems, Prof. Shuji Nakamura of the University of California at Santa Barbara and Nichia for the Pioneering Development of Large-Venue, Large-Screen Direct View Color Video Displays.
	Daily Nexus: UCSB Professor Develops Efficient Light Displays(link)
	Nitrides Seminars University of California Santa Barbara Dr. Elison Matioli from Massachusetts Institute of Technology Dept. of Electrical Engineering and Computer Science was a guest speaker at the September 7th Nitrides Seminar. Seminar topic: High Brightness Polarized Light Emitting Diodes. Dr. Matioli is pictured here with Professors Weisbuch, Nakamura, DenBaars and Speck.
	SSLEC research conducted in the field of Power Electronics(link) 30 August 2011 More positive threshold with Al2O3 and m-plane nitride semis The USA's University of California Santa Barbara (UCSB) and Japan's Rohm Co Ltd have produced enhancement-mode (E-mode) nitride semiconductor heterojunction field-effect transistors (HFETs) with a threshhold voltage of +sV and on/off current ratio of 4x106 [Tetsuya Fujiwara et al, Appl. Phys. Express, vol4, p096501, 2011]. Enhancement-mode, or normally-off', operation is seen as being particularly important for power switching devices because one wants such devices to switch off if they fail,
	Switching faces improves high-speed HEMTs(link) July 12, 2011 Conventional GaN HEMTs are excellent devices over a wide frequency range. However, for great performance at really high speeds, it's best to switch from the standard gallium face to a nitrogen one, according to UCSB's Umesh Mishra. (2011-07Compoundsemi_UM)
	UCSB Reveives High Rankings in Materials Research (link) (Santa Barbara, Calif.) Materials research at UC Santa Barbara ranks second in the world in terms of citation impact a method for comparing the quality of research according to a new report by Thomson Reuters. Additional link to Thomas Reuters:(link)
	Claude Weisbuch Awarded 20,000 Euro Leon Brillouin Prize June 20th, 2011(link) Claude Weisbuch has been awarded the 20,000 Euro Leon Brillouin Prize from Société Française d Optique. Claude will be honored at the Société Française d'Optique meeting first week in July in Marseille. (2-11-06_CW_Le-Grand-Prix-Leon-Brillouin2011)
	LED droop: Theorist uncover the Auger mechanisms Compound Semiconductor (link) Calculations by Chris Van de WAlle's team from the University of California, Santa Barbara, (UCSB) expose two forms of indirect Auger recombination as the primary causes of LED droop
	N-polar HEMT catches up conventional cousins Compound Semiconductor (link) At 4 GHz, MOCVD-grown N-polar HEMTs on sapphire deliver the same power density as conventional G-polar equvalents
	LED Efficiency Puzzle Solved by UC Santa Barbara Theorists Eurekalert.org (link) UCSB Engineering (link) Compound Semiconductor (link) Researchers at the University of California, Santa Barbara, say they've figured out the cause of a problem that's made light-emitting diodes (LEDs) impractical for general lighting purposes. Their work will help engineers develop a new generation of high-performance, energy-efficient lighting that could replace incandescent and fluorescent bulbs.
	Society for Information Display's Annual Display Week Hits the Red Carpet With a Blockbuster Line Up PR Newswire (link) 49th annual SID International Symposium, Seminar and Exhibition, known as Display Week, will be held May 15-20, 2011 at the Los Angeles Convention Center. The keynotes kick off the four-day Symposium, which runs Tuesday, May 17 through Friday, May 20, and features 72 sessions with 265 oral and 200 poster presentations that address a broad range of leading-edge topics. The morning keynotes will conclude with Shuji Nakamura, professor of materials development at the University of California, Santa Barbara. Nakamura will discuss how high-brightness LEDs and visible laser diodes have led to new display application areas such as LED-backlit TVs and DVD blue-ray players.
	Nitrides Seminars *University of California Santa Barbara* Dr. Partha Dutta from Rensselaer Polytechnic Institute in New York was a guest speaker at the February 25th Nitrides Seminar. Seminar topic: High Efficiency Phosphors for Full Spectrum Solid State Lighting Technologies. Dr. Dutta is pictured here with Professors Nakamura and DenBaars.
	Giving LEDs the Blues was the Key to Replacing the Incandescent Bulb. ieee Spectrum (pdf) Back in the 20th century, just about the only LED you normally saw was the one that lit up when your stereo was on. By the noughties, tiny light-emitting diodes were also illuminating the display and keypads of your mobile phone. Now they are backlighting your netbook screen, and soon they'll replace the incandescent and compact fluorescent lightbulbs in your home.
	Next-to-the-Best Technologies of 2000-2010 ieee Spectrum (pdf) These innovation just barely missed the cut for the Top 11 list. Included: The rise and fall of the optical disc.
	Nitrides Seminars *University of California Santa Barbara* Dr. Heon Lee and his Ph.D. student Kyeong-Jae Byeon were guest speakers at the January 26th Nitrides Seminar. Seminar topic: Nanoimprint-based patterning process to improve light extraction efficiency of GaN-based light-emitting diodes. Roy Chung of UCSB was their host. *University of California Santa Barbara* Dr. Wolfgang Scheibenzuber was a guest speaker at the January 31st Nitrides Seminar. Seminar topic: Optical characterization of GaN-based laser diodes in spectral and temporal domain. Also pictured here are Qimin Yan and Emmanouil (Manos ) Kioupakis.
	Bringing Light Into the World Pacific Coast Business Times (pdf) (link-subscription required) A team of engineers at UC Santa Barbara has banded with nonprofits to send a reading light designed on the South Coast to thousands of people in Ghana, Haiti and other developing nations by the end of this year.
	Nitride Solar Cell Achieves Peak EQE of 72% Semiconductor Today (link) University of California Santa Barbara (UCSB) researchers have produced nitride semiconductor photovoltaic devices with external quantum efficiencies (EQE) of up to 72% [Elison Matioli et al, Appl. Phys. Lett., vol98, p021102, 2011]. One of the researchers, Claude Weisbuch, is also associated with Ecole Polytechnique in France.
	Chris G. Van de Walle Named AAAS Fellows UC Santa Barbara Engineering (link) Professor Van de Walle has been chosen to receive the AAAS fellowship award for his pioneering research on the theory of semiconductor interfaces and defects in solids, and for leadership in computational physics and materials science.

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