LIGHTimes News Staff
January 12, 2012…Researchers at Osram Opto Semiconductors have succeeded in manufacturing high-performance blue and white LED prototypes in which the light-emitting gallium-nitride layers are grown on silicon wafers with a diameter of 150 millimeters (approx. 6 inches). The silicon wafers replace the sapphire substrates commonly used in the industry up to now, with no loss of quality. Osram says that the LED chips are already in the pilot stage and are being tested under practical conditions. Osram Opto Semiconductors expects its first LEDs on silicon to be available on the market in as little two years.
Silicon is an attractive alternative to sapphire because of its low cost of production and its already widespread use in computers and electronics.
Osram Opto says that it has achieved 634mW of brightness for its blue Golden Dragon UX-3 LED on silicon at 350mA. The company says that with a white phosphor the resulting LED would emit 140 lm and have an efficacy of to 127 lm/W at 4500K.
Bridgelux, another LED maker, has also greated blue GaN LEDs on 8-inch silicon wafers, The Bridgelux LEDs emit 591mW at 2.85 V and 3.50 mA. Bridgelux also announced at that time in August 2011 that its warm white LEDs on silicon were proven to have 125 lm/W efficacy (Ref: coverage).
