Bridgelux Inc. is bullish on the future of its GaN-on-Si LED, which it claimed successfully demonstrated an output of 135 lumens of light per watt, making it the first silicon substrate LED capable of commercial-grade output.
The semiconductor technology developer for solid-state lighting, however, cautioned that applications using the technology may still be two to three years down the road.
California-based Bridgelux has raised some $110 million in venture capital since its founding in 2002. While most epitaxial wafers for LED use sapphire or silicon carbide substrates as the starting material, large-diameter sapphire and silicon carbide substrates are expensive and more difficult to process. Gallium nitride grown on low-cost silicon wafers that come in 150mm, 200mm and 300mm diameters are a viable alternative as it offers a 75 percent cost reduction, the company said.
Bridgelux said it used a single 1.5mm diameter LED operated at 350mA with a color correlated temperature of 4730K to achieve the 135-lumen output. The LEDs require 2.9V at 350mA and less than 3.25V at 1A. The company believes that it will be able to optimize the epitaxy process on 200mm-diameter silicon wafers.
"The significantly reduced cost-structures enabled by Silicon-based LED technology will continue to deliver dramatic reductions in the up-front capital investment required for solid state lighting," Bridgelux CEO Bill Watkins said in a statement. "In as little as two to three years, even the most price-sensitive markets, such as commercial and office lighting, residential applications, and retrofit lamps will seamlessly and rapidly convert to solid-state lighting."
