Increasing the brightness of III-Nitride light emitting devices

摘要

LEDs employing a III-Nitride light emitting active region deposited on a base layer above a substrate show improved optical properties with the base layer grown on an intentionally misaligned substrate with a thickness greater than 3.5 mum. Improved brightness, improved quantum efficiency, and a reduction in the current at which maximum quantum efficiency occurs are among the improved optical properties resulting from use of a misaligned substrate and a thick base layer. Illustrative examples are given of misalignment angles in the range from 0.05° to 0.50°, and base layers in the range from 6.5 to 9.5 mum although larger values of both misalignment angle and base layer thickness can be used. In some cases, the use of thicker base layers provides sufficient structural support to allow the substrate to be removed from the device entirely.