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.
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 8-inch silicon wafers, without bowing at room temperature. This improves the manufacturability of GaN LEDs on silicon substrate.
“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
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The expectation is that by 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.
“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),” stated 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,” said Lester.
The company plans to have 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 1 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 8-inch LED wafers with median wavelength of 455nm.