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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

Active Publication Date: 2013-05-28
NAT TECH & ENG SOLUTIONS OF SANDIA LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention relates to improving the efficiency and performance of III-N LEDs. The invention uses tailored doping in the quantum barriers of a multiple-quantum-well LED to balance the radiative recombination among the multiple-quantum-wells and reduce electron leakage. This results in more symmetric carrier transport and uniform carrier distribution, leading to a more efficient LED.

Problems solved by technology

The confinement of electrons to the active region of III-N LEDs is limited by the: inefficient electron capture into polar quantum wells, electron-attracting properties of electron-blocking layer, asymmetry in electron and hole transport, and unfavorable p-doping in the AlGaN electron-blocking layer for high Al content.
This result can be attributed to a more symmetric carrier transport and uniform carrier distribution which help to reduce electron leakage and thus reduce the efficiency droop.

Method used

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Examples

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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,...

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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.

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...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): H01S5/00H01S5/183H01S5/20H01S5/34
CPCH01S5/3413H01S5/2018H01L33/06H01S5/309B82Y20/00H01S5/18308H01S5/34333H01L33/025
Inventor CRAWFORD, MARYKOLESKE, DANIELCHO, JAEHEEZHU, DINOEMAUN, AHMEDSCHUBERT, MARTIN F.SCHUBERT, E. FRED
Owner NAT TECH & ENG SOLUTIONS OF SANDIA LLC
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