Toshiba Japan has developed an LED that emits UV light with 50% higher efficiency than conventional LEDs. The problem with existing white LEDs is that they are made by coating phosphors on blue LEDs and too weak to light bigger areas such as parking lots or supermarkets.
Toshiba says their prototype UV LED is made by placing a layer of aluminum nitride between the sapphire substrate and the light-emitting layer of gallium nitride to avoid fissures, resulting in higher efficiency. The LED is coated with green, red and blue phosphors. It produces light with a wavelength of 383nm and a brightness of 23mW (at a current of 20mA). This is up to 8mW higher than existing LEDs.
Toshiba’s goal is to offer their new white LEDs as an alternative to fluorescent lamps by 2010. Osaka-based Mitsui Kinzoku is currently doing similar research.
Via Nikkei [registration required, paid subscription]