Berkeley Researchers Improve Solar Cell Efficiency By Making it Emit More Light
CompoundSemi News Staff
April 23, 2012...Researchers from the University of California, Berkeley, have suggested that solar cells should be more like LEDs. The researchers claim to have demonstrated that solar cells should be designed to emit light as well as absorb it to maximize efficiency. The research team from Bereley will present its findings at the Conference on Lasers and Electro Optics (CLEO: 2012), to be held May 6-11 in San Jose, Calif.
“What we demonstrated is that the better a solar cell is at emitting photons, the higher its voltage and the greater the efficiency it can produce,” says Eli Yablonovitch, principal researcher and UC Berkeley electrical engineering professor.
The researchers came across a thermodynamic link between absorption and emission of light. “If you have a solar cell that is a good emitter of light, it also makes it produce a higher voltage,” which in turn increases the amount of electrical energy that can be harvested from the cell for each unit of sunlight, graduate student Owen Miller asserted.
In 2011, Alta Devices of the Bay Area, which Yablonovitch co-founded, created a GaAs-based prototype solar cell that achieved a record 28.3 percent efficiency in part by allowing more light to escape. They increased the reflectivity of the rear mirror, which sends incoming photons back out through the front of the device. Yablonovitch says he hopes researchers will be able to use this technique to achieve efficiencies close to 30 percent in the coming years for single junction cells and help improve all solar cells.
April 23, 2012...Sensor Electronic Technology, Inc (SETi) of Columbia, South Carolina USA, announced record efficiencies of UV LEDs operating in the germicidal UV-C range of 11% external quantum efficiency (EQE) with a corresponding wall-plug efficiency (WPE) of 8%. This was achieved under the DARPA Compact Mid-Ultraviolet Technology (CMUVT) program in collaboration with Army Research Laboratories (ARL).
The company notes that this is more than 5X improvement in performance. The company attributes this improvement primarily to improved light extraction from encapsulated LED chips with a novel transparent p-region and a reflective contact and reductions in defect density in the LED structure on a sapphire substrate.
SETi points out that traditionally, UV LEDs are manufactured with GaN p-layers, due to the difficulties of p-doping AlGaN materials. However, GaN absorbs wavelengths shorter than 365nm, thereby reducing the extraction efficiency of short wavelength UV LEDs. SETi says it has developed a new p- type region using doped AlGaN, which is transparent in the UVC range. The company says that this along with a transparent p-contact significantly increases extraction efficiencies.
SETi reduced dislocation densities in quantum well structures with further development of its MEMOCVD® growth process on sapphire. SETi demonstrated threading dislocation densities (TDD) of less than 2x108 (measured by TEM) which the company claims led to internal quantum efficiency (IQE) of 60%. The encapsulated LEDs measuring 350um x 350um, emit at 278nm. They emitted 9.8mW at 20mA (the highest ever reported for Short wavelength UV) and 30mW at 100mA.
Veeco Invests in R&D Facility in Seoul and Lasertel Inc. Buys Veeco MBE System
CompoundSemi News Staff
April 23, 2012...Veeco Instruments has invested in a new research and development facility in Seoul, Korea to advance high brightness LED technology. The company recently participated in an investment forum signing ceremony at the 2012 Korea Investment Forum in New York City to commemorate the company’s substantial investment in the new R&D facility. The Investment Forum event, jointly sponsored by the Korea Trade-Investment Promotion Agency (KOTRA) and the Korea Ministry of Knowledge Economy (MKE), brought together government officials, investors, industry experts and business leaders from South Korea and the United States to celebrate and promote investment in South Korea by U.S.-based companies.
In other Veeco news, the company reported that Lasertel, Inc. of Tucson, Arizona USA a subsidiary of Selex Galileo Inc., a Finmeccanica company, purchased a second high-throughput, multi-wafer GEN200(R) Edge(TM) Molecular Beam Epitaxy (MBE) production system to increase its laser diode manufacturing capacity. This brings their in-house complement of MBE tools to four. The latest will reportedly be used to accelerate the development of next-generation, high performance diode laser products. The expansion is planned to be completed by Q4, 2012.
"The additional GEN200 Edge production MBE system provides the extra capacity required to support the increased demand for Lasertel devices. The GEN200 system offers advanced automation, precise process control, and in-situ process monitoring. It is the core enabling technology for Lasertel's leading-edge, high performance semiconductor diode laser devices," says Mark McElhinney, President of Lasertel.
TriQuint to Jointly Develop GaN MMICs with U.S. Army Research Laboratory
CompoundSemi News Staff
April 16, 2012...TriQuint Semiconductor, Inc. of Hillsboro, Oregon USA announced that it has signed a Cooperative Research and Development Agreement (CRADA) with the U.S. Army Research Laboratory (ARL) to develop gallium nitride (GaN)-based ICs. The CRADA to explore and fabricate high frequency and mixed signal circuits is reportedly aims to accelerate new programs for communications, radar, electronic warfare, and similar applications.
TriQuint's new agreement with the ARL is designed to stimulate high performance monolithic microwave integrated circuit (MMIC) development. The ARL's design and testing capabilities will be leveraged with TriQuint's MMIC fabrication, testing and packaging expertise. The new agreement leverages technology TriQuint created through on-going R&D programs. According to TriQuint, the circuits created are expected to be based on the company's new E/D (enhancement-depletion mode) GaN technology.
"Creative partnerships through Cooperative Research and Development Agreements encourage outside businesses and university organizations to share in the discovery of and investment in technologies. In this case, ARL is leveraging industrial fabrication capabilities allowing ARL to maximize its return on investment," said John Miller, Army Research Laboratory Director. "These advanced IC processes, coupled with ARL's design expertise, could lead to innovations and advancements in both military and consumer applications in communications, radar and electronic warfare."
Ball Aerospace Awards Emcore Solar Panel Manufacturing Contract
CompoundSemi News Staff
April 16, 2012...Emcore Corporation based in Albuquerque, New Mexico USA, reports that Ball Aerospace & Technologies Corporation (BATC) awarded it a contract to design, manufacture, test, and deliver solar panels for a new spacecraft. Emcore indicated that the two year contract has a total contract value of nearly $6 million.
Emcore's ZTJ multi-junction solar cells will populate BATC. Emcore claims that the ZTJ is currently the highest performance space-grade solar cell available in volume production to the global market. Production of the solar cells and panels will take place at Emcore's manufacturing facilities located in Albuquerque.
Emcore is a leading manufacturer of highly-efficient radiation-hard solar cells for space power applications. The radiation-hardened multi-junction cells have a beginning-of-life (BOL) conversion efficiency nearing 30% and the option for a patented, onboard monolithic bypass diode. The company says that they provide the highest available power to interplanetary spacecraft and earth orbiting satellites.
"We are very pleased to receive this award from Ball Aerospace & Technologies Corporation and recognize their confidence in our capabilities to manufacture and deliver the solar panels for this important mission," said Christopher Larocca, Chief Operating Officer for Emcore.
LED-IT Fusion Technology Center of Korea Orders Veeco MOCVD System
LIGHTimes News Staff
April 19, 2012...Veeco Instruments Inc. of Plainview, New York USA, announced that LED-IT Fusion Technology Research Center (LIFTRC) of Korea selected its TurboDisc K465i GaN metal organic chemical vapor deposition (MOCVD) system for research and development of HB LEDs, including green and (UV) varieties. Veeco also introduced the Spector-HT Ion Beam Deposition (IBD) System to create thin film coatings for the optical market.
LED-IT Fusion Technology Research Center seeks to commercialize LED-IT fusion technology. Dr. Ja-Soon Jang, Chief Director, LIFTRC, and Professor, Department of Electronic Engineering, at Yeungnam University commented, "Veeco's K465i enables us to conduct research and development of next generation LED technology on a fully-automated, low cost of ownership platform."
William J. Miller, Ph.D., Veeco’s Executive Vice President, Process Equipment, commented, “We are very pleased that LED-IT Fusion Technology Research Center, a top research organization, recognizes the benefits of the TurboDisc K465i MOCVD System. We look forward to supporting LIFTRC and their partners and believe Korea will continue to drive the advancement of LED technology.”
Yole Development Predicts Market for Key RF Components Will Reach $4.7 Billion in 2016
CompoundSemi News Staff
April 9, 2012...Yole says that while radio-front end market is very fragmented in terms of architectures, a few types of components are key with filters or duplexers, power amplifiers, and antenna switches at the heart of every cell phone radio.
“Those components represent a $3.6B market in 2011 already, growing at a 5.6% rate annually until 2016,” says Laurent Robin, activity leader, Yole Développement.
Yole asserts that filters and duplexers are the most dynamic market segment of this market. Sale of duplexers is growing at a 10.5% rate annually. Yole Development says this market will reach $1.7B in 2016. The company says that smartphones' wide use of WCDMA bands and LTE is a new strong driver. Depending on each band, SAW or BAW developments are candidates for further growth. The company says that while Epcos and Murata dominate the SAW area, Avago and TriQuint are in fierce competition in the BAW segment.
Yole notes that despite maturing, many new technologies are impacting the PA market. Also converged PAs and more broadband PAs are increasingly accepted. GaAs still dominates the PA market, but CMOS PAs are gaining at the low end side of the market, Yole indicated.
Yole predicts that Silicon-on-insulator (SOI) technology could be used for PAs soon.
According to Yole, the antenna switches segment, which includes Peregrine Semiconductor, is evolving towards more performance for the new LTE bands and increasing number of throws. Yole says it also observed massive adoption of SOI technology in the segment since 2010.
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