Gallium nitride based light emitting diodes (LEDs) for energy efficient lighting and displays

摘要

InGaN based materials have been used to fabricate LEDs fabricated from gallium nitride materials have lead to the realization of high-efficiency white solid-state lighting. Using advanced light extraction structures we have fabricated advanced GaN white LEDs structures which exhibit luminous efficacy greater than 150 lm/Watt, and external quantum efficiencies higher than 60% at low current densities(20A/cm2) on c-plane. New LED structures grown on semipolar orientations of bulk GaN have shown remarkable efficiencies with EQE greater than 45% at high current densities(400A/cm2). Equally impressive are GaN based blue and green laser diodes are displaying high efficiencies at even higher current densities (>2000A/cm2). Further improvements in materials quality and cost reduction are necessary for wide-spread adoption of LEDs for lighting. Solid-state lighting has the potential to achieve 85% energy efficiency, corresponding to 255 lm/watt, and be able to run entirely off sustainable energy sources such as either solar, thermoelectric or wind.