[August 18, 2011] LED developer Bridgelux is claiming breakthrough... Tweet (Electronics Weekly (UK) Via Acquire Media NewsEdge) LED developer Bridgelux is claiming breakthrough power efficiencies for gallium nitride on silicon (GaN-on-Si) devices. The company claims LED performance levels comparable to high-end sapphire-based LEDs. "This key innovation is a game-changer for the industry, delivering dramatic reductions in the up-front capital investment required for solid state lighting," said Bill Watkins, Bridgelux CEO Cost is still seen as a barrier to widespread use of LEDs in general home lighting. In June the US Department of Energy said costs were too high and "their learning curve not sufficiently aggressive". It's target is to get the cost down to $2.20 per thousand lumen (klm) within five years from the current $18klm. The expectation is that growing GaN on larger silicon wafers that are compatible with modern semiconductor manufacturing can reduce the cost of high-brightness LEDs for general lighting applications. Conventional LEDs are made using sapphire or silicon carbide substrates as the starting material. Both are more expensive than silicon. According to Bridgelux, warm white LEDs constructed from the GaN on Si chips delivered 125 Lm/W at a colour temperature of 2940K and CRI of 80. Cool white LEDs showed efficiencies as high as 160 Lm/W at a CCT of 4350K. The devices use a proprietary buffer layer technology for growing GaN layers on eight-inch silicon wafers, without bowing at room temperature. This improves the manufacturability of GaN LEDs on silicon substrate. "The performance levels that we announced today are the highest Lm/W values yet published for GaN-on-Si and rival the best commercial LEDs grown on sapphire or silicon carbide (SiC)," said Dr Steve Lester, Bridgelux chief technology officer. "We are very pleased with the pace of our progress in this area, and we will continue to aggressively develop our GaN-on-Si processes in order to drive the migration of LED commercial production from sapphire to silicon substrates," he said. The company plans to have its first commercial GaN-on-Si products ready for the market within two years. Encapsulated 1.5mm blue LEDs emit 591mW with wall plug efficiencies as high as 59% at 350mA, exceeding any published values. At a drive current of one amp the LEDs emitted 1.52W of blue power at a forward voltage of 3.21V, resulting in a wall plug efficiency of 47%. Wavelength uniformity of sigma 6.8nm has been demonstrated for eight-inch LED wafers with median wavelength of 455nm. Bridgelux www.bridgelux.com (c) 2011 Reed Business Information - UK. All Rights Reserved. [ Back To TMCnet.com's Homepage ]