Startup Soraa says its LEDs have set a new performance record, which will result in cheaper and brighter LED light bulbs.
The company yesterday said its second-generation LEDs can handle a relatively high current—100 amps per square centimeter—which means its bulbs will produce more light and be more efficient than conventional LEDs. Its LEDs emit ten times more light per area and can handle higher current rates without causing performance or reliability problems, according to Soraa chief technology officer Mike Krames.
The performance gain comes from the fact that Soraa makes LEDs by growing gallium nitride on a substrate of gallium nitride (GaN on GaN). Most LEDs are made with GaN on sapphire, but having the same semiconductor material reduces the mismatch in the crystal structure between the two layers. That means there are fewer defects and the LED can produce more light from incoming current, he says.
The result, published in the Applied Physics Letters, is significant because GaN-on-GaN LEDs offer one potential pathway for improving the performance of LED lighting. Other companies, including Bridgelux and Osram Opto Semiconductors, are working to make LEDs using gallium nitride on silicon wafers, which promises to cut the production costs. (See Cheaper LED Lightbulbs Are on the Way.)
There are signs that the pace of improvement with existing methods is slowing down. Cree, which makes LEDs using a silicon carbide substrate, announced it achieved 200 lumens per watt in late last year. But there are “certain physical limits” to reaching other big milestones in the future, components product marketing manager Paul Scheidt told me at the time.
Soraa’s Krames says that, by contrast, the company’s technology is at the early part of its performance improvement curve, which should continue “for many years to come.”
The company is now selling an MR16 spot light using its LED. A bulb designed to replace a 50-watt halogen consumes 12.2 watts with a color rendering index of 95, which means it produces high-quality light. Using more expensive gallium nitride LEDs adds more expense, but Krames says the performance improvement outweighs the cost and buyers, typically at commercial buildings, get a return on investment in a year.
The company plans to use its second-generation chip in future MR16 products and other types of lamps, he says.