High efficiency III-nitride light-emitting diodes

a light-emitting diode, high-efficiency technology, applied in the field of light-emitting diodes, can solve the problems of limited electron confluence to the active region of iii-n leds, reduce efficiency droop, etc., and achieve the effect of reducing efficiency droop and electron leakag

US8451877B1Active Publication Date: 2013-05-28NAT TECH & ENG SOLUTIONS OF SANDIA LLC
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Patents(United States)
Current Assignee / Owner
Publication Date
2013-05-28
Patent Text Reader

Abstract

Tailored doping of barrier layers enables balancing of the radiative recombination among the multiple-quantum-wells in III-Nitride light-emitting diodes. This tailored doping enables more symmetric carrier transport and uniform carrier distribution which help to reduce electron leakage and thus reduce the efficiency droop in high-power III-Nitride LEDs. Mitigation of the efficiency droop in III-Nitride LEDs may enable the pervasive market penetration of solid-state-lighting technologies in high-power lighting and illumination.
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Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 61 / 316,518, filed Mar. 23, 2010, which is incorporated herein by reference.STATEMENT OF GOVERNMENT INTEREST

[0002] This invention was made with Government support under contract no. DE-AC04-94AL85000 awarded by the U.S. Department of Energy to Sandia Corporation. The Government has certain rights in the invention.FIELD OF THE INVENTION

[0003] The present invention relates to light-emitting diodes and, in particular, to III-Nitride light-emitting diodes that use tailored doping of quantum barriers to symmetrize carrier transport and achieve uniform carrier distribution among multiple-quantum-wells, thereby helping to reduce electron leakage and thus reduce efficiency droop at high injection currents.BACKGROUND OF THE INVENTION

[0004] Light-emitting diodes (LEDs) are used in a wide variety of applications, including in high-power lighting and illumination. LEDs present many ad...

Examples

Embodiment Construction

[0016]FIG. 1 shows a typical MQW heterostructure of a gallium-nitride-based LED. This exemplary p-side up device is built on a substrate 1, such as sapphire, that is suitable for epitaxial growth of the heterostructure. An undoped GaN epilayer 2 is grown on the sapphire substrate to enable the growth of smooth, crystalline heterostructure films. An n-type GaN layer 3, comprising GaN doped with a group IV donor impurity, such as silicon, is grown on the epilayer 2. This n-type layer 3 serves as a source of electrons. In this example, a five MQW active region 10 is then grown on the n-type GaN layer 3, comprising a plurality of alternating quantum barrier (QB) layers 5 surrounding central quantum well (QW) layers 4. For example, the QWs 4 can comprise GaN, InGaN, AlGaN, or AlInGaN. For example, the color of the light emitted from the active region 10 can be controlled by varying the gallium-to-indium ratio in InGaN QWs. For example, the barrier layers 5 can comprise GaN, GaInN, AlGaN,...