Technology | Jan 31, 2012

Removing Impurities from QDs Made by Cation-Exchange Techniques May Lead to Affordable QD-Products

Luminescence of CdSe/CuS nanocrystals prepared by cation-exchange. On the left are crystals prior to purification, on the right are the same nanocrystals after impurities have been removed (courtesy of Lawrence Berkeley National Laboratory) To the lengthy list of serendipitous discoveries – gravity, penicillin, the New World – add this: Scientists with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have discovered why a promising technique for making quantum dots and nanorods has so far been a disappointment. Better still, they’ve also discovered how to correct the problem. Read more »

White Paper | Technology | Jan 13, 2012

Success in Research: First Gallium-Nitride LED Chips on Silicon in Pilot Stage

The process diagram shows the production of a UX:3 chip on a silicon wafer Researchers at Osram Opto Semiconductors have succeeded in manufacturing highperformance prototypes of blue and white LEDs, in which the light-emitting gallium-nitride layers are grown on silicon wafers with a diameter of 150 millimeters. The silicon replaces the sapphire commonly used until now without a loss in quality. Already in the pilot stage, the new LED chips are to be tested under practical conditions, meaning that the first LEDs on silicon from Osram Opto Semiconductors could hit the market in just two years. Read more »

Technology | Dec 23, 2011

New Developed Technique Makes it Easier To Etch Semiconductors - Especially III-V Semiconductors

Metal-assisted chemical etching uses two steps. First, a thin layer of gold is patterned on top of a semiconductor wafer with soft lithography (top-left). The gold catalyzes a chemical reaction that etches the semiconductor form the top down, creating three-dimensional structures for optoelectronic applications (bottom-left). A scanning electron microscope image of “nanopillars” etched in gallium arsenide (right). | Graphic & Image by Xiuling Li Creating semiconductor structures for high-end optoelectronic devices just got easier, thanks to University of Illinois researchers. The team developed a method to chemically etch patterned arrays in the semiconductor gallium arsenide, used in solar cells, lasers, light emitting diodes (LEDs), field effect transistors (FETs), capacitors and sensors. Led by electrical and computer engineering professor Xiuling Li, the researchers describe their technique in the journal Nano Letters. Read more »

White Paper | Technology | Dec 15, 2011

Independent Study Demonstrating that Pink Sapphire Produces Highest Transmission Colorless Epi-Wafers

The analysis concludes there is no correlation between the trace color found in the wafers and the color of the GT ASF-grown material GT Advanced Technologies Inc. announced the release of a case study that details the findings of a series of blind material studies conducted to evaluate the impact of sapphire color on the LED manufacturing process. The studies demonstrated that all sapphire, regardless of source, exhibits color at the core level, that the pink hue of GT Advanced Sapphire Furnace (ASF™) material is not indicative of impurities, and that pink ASF sapphire does not have an adverse affect on the LED manufacturing process nor does it require extra steps or incremental costs to remove the pink hue. In addition, it was demonstrated that GT ASF pink sapphire material makes the lowest absorption, highest transmission epi-wafers of the samples examined. Read more »

Technology | Nov 30, 2011

LEDs Produced on Patterned Sapphire Substrates Improve Overall Efficiency at Lower Costs

Structured surface produced by etching processes promise improved light extraction MicroTech has developed a wet process station for the etching of PSS (Patterned Sapphire Substrate) wafers used to increase light extraction and efficiency in high brightness LEDs. The wet station can improve manufacturing throughput, a major stumbling block to making LEDs price competitive with fluorescent lighting. Read more »

Technology | Nov 16, 2011

In New Quantum-Dot LED Design, Researchers Turn Troublesome Molecules to Their Advantage

The new structure allows more effective control over the flow of electrical current By nestling quantum dots in an insulating egg-crate structure, researchers at the Harvard School of Engineering and Applied Sciences (SEAS) have demonstrated a robust new architecture for quantum-dot light-emitting devices (QD-LEDs). Read more »

Technology | Nov 10, 2011

Los Alamos Researchers Unravel the Mystery of Quantum Dot Blinking

Los Alamos researchers have shown that blinking of QDs can be controlled and even completely suppressed electrochemically Research by Los Alamos scientists published today in the journal Nature documents significant progress in understanding the phenomenon of quantum-dot blinking. Their findings should enhance the ability of biologists to track single particles, enable technologists to create novel light-emitting diodes and single-photon sources, and boost efforts of energy researchers to develop new types of highly efficient solar cells. Read more »

Technology | Oct 27, 2011

Competing LEDs: High-quality White Light Produced by Four-Color Laser Source

Four laser beams — yellow, blue, green and red — converge to produce a pleasantly warm white light. Results suggest that diode-based lighting could be an attractive alternative to increasingly popular LED lighting, themselves an alternative to compact-florescent lights and incandescent bulbs. (Photo by Randy Montoya) The human eye is as comfortable with white light generated by diode lasers as with that produced by increasingly popular light-emitting diodes (LEDs), according to tests conceived at Sandia National Laboratories. Both technologies pass electrical current through material to generate light, but the simpler LED emits lights only through spontaneous emission. Diode lasers bounce light back and forth internally before releasing it. Read more »

Technology | Oct 18, 2011

EPISTAR LAB Launched a New Platform to Achieve 3.0V White LED Chip at 1A Operation

Comparison of voltage to current and luminous flux to current between the new FOC chip structure and a conventional chip EPISTAR LAB has developed a technology suitable for lighting applications to reach high efficacy by a single chip in size of 55mil for white LED to ease the complicated packaging of wire bonding. This technology enables a white LED with a lower voltage down to 3.0V at 1A operation and junction temperature of 85°C (3.2V at room temperature). Read more »

Technology | Oct 17, 2011

609 nm Red LED Prototype from OSRAM Opto Semiconductors Achieves Record Efficiency

World record in the OSRAM laboratory: 201lm/W – 61% efficiency (WPE) A red high-power LED has set a new efficiency record in an OSRAM Opto Semiconductors R&D lab with an electro-optical efficiency of 61%. The 1 mm2 chip housed on a laboratory package emits at a wavelength of 609 nm (λ-dom) and has achieved a record value of 201 lm/W at an operating current of 40 mA. At a typical operating current of 350 mA its luminous efficacy is still an impressive 168 lm/W, which means that even at this high wattage more than half of the electrical energy is converted into light. Read more »

Technology | Aug 10, 2011

BRIDGELUX Boost Efficiency Record for GaN-on-Silicon Technology LEDs to 160lm/W

Growing LEDs on low-cost large diameter silicon substrates needs special knowledge Bridgelux Inc., a leading developer and manufacturer of LED lighting technologies and solutions, has shattered its previous industry record for highest Lumen per Watt values for Gallium Nitride on Silicon (GaN-on-Si). Using its proprietary buffer layer technology, the company has demonstrated growth of crack-free GaN layers on 8-inch silicon wafers, without bowing at room temperature, extending the company’s lead in driving the performance and manufacturability of GaN LEDs on silicon substrate. Read more »

Technology | Aug 02, 2011

Cree Prototype Exceeds DOE’s 21st Century Lamp L Prize Requirements

Cree's "21st Century Lamp" prototype delivers 1,300 lumens at 152 lumens per watt Demonstrating the future of lighting, Cree, Inc. today unveiled a concept LED light bulb from its lighting research and development team. Redefining what is possible with high-performance LED lighting, the lamp delivers more than 1,300 lumens at 152 lumens per watt (LPW) using Cree TrueWhite® Technology. Cree’s prototype LED light bulb exceeds the performance goals set by the U.S. Department of Energy (DOE) for the 21st Century Lamp, the third category in its L Prize competition. Read more »

Technology | Jul 26, 2011

New 3-D Photonic Crystal has both Electronic and Optical Properties

Using an epitaxial approach, researchers developed a 3-D photonic crystal LED, the first such optoelectronic device. [Graphic by Eric Nelson] In an advance that could open new avenues for solar cells, lasers, metamaterials and more, researchers at the University of Illinois have demonstrated the first optoelectronically active 3-D photonic crystal. To test their technique, the group built a 3-D photonic crystal LED the first such working device. Read more »

Technology | Jul 15, 2011

Translucent Presents Novel Mirrored Si™ Process for Low-Cost LED Growth

Mirrored Si™ is a silicon substrate with an epitaxial grown (crystalline) Distributed Bragg Reflector that can be used as a virtual substrate for the epitaxy of the device structure Translucent GaN-on-Si wafer template with embedded DBR mirrors enables low-cost LED growth, the novel Mirrored Si™ process will be presented in a special session at the International Conference on Nitride Semiconductors in Glasgow, Scotland. Read more »

Technology | Jul 12, 2011

RoseStreet Labs Scientists Demonstrate First Long Wavelength LED Based on InGaN On Silicon Technology

RoseStreet Labs demonstrated the first green InGaN LED on silicon technology to be efficient and cost competitive RoseStreet Labs, (RSL), announced today the world’s first demonstration of a long wavelength LED device utilizing low cost silicon wafer substrates. Green and longer wavelength LEDs have been sought after by both science and industry for an extensive period of time because they would fill a high-value gap in the rapidly growing global LED market for lighting and illumination where energy efficiency, low cost and miniaturization are critical product characteristics. Read more »

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Edison Opto UVA + White & UVC Series Customize Design Solution

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J Series® 2835 G Class 3V LEDs Now Shine Even Brighter

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LUXEON 5050 HE Delivers Higher Efficacy in a High-power LED

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NICHIA LED Technology Presented at LICHTWOCHE München

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