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LED Device Structures with Minimized Light Re-Absorption

Technology Benefits

Reduces light reflections  Increased  light extraction efficiency

Technology Application

LED manufacturing     This technology is available for licensing.

Detailed Technology Description

Researchers at the University of California, Santa Barbara have developed a III-nitride light emitting diode (LED), in which light can be extracted from two surfaces of the LED before entering a shaped optical element and subsequently being extracted to air. This technology minimizes the light re-absorption at the LED active region by eliminating light reflection at the p-type side surface of the LED chip.

Supplementary Information

Patent Number: US8124991B2
Application Number: US2008181100A
Inventor: Iso, Kenji | Asamizu, Hirokuni | Saito, Makoto | Sato, Hitoshi | DenBaars, Steven P. | Nakamura, Shuji
Priority Date: 26 Jul 2007
Priority Number: US8124991B2
Application Date: 28 Jul 2008
Publication Date: 28 Feb 2012
IPC Current: H01L003300 | H01L003314 | H01L003362
US Class: 257098 | 257091 | 257094 | 257095 | 257096 | 257097 | 257099 | 257103 | 257E23028 | 257E25032 | 257E33054 | 257E33068 | 257E33077 | 438029 | 257E2528
Assignee Applicant: The Regents of the University of California
Title: Light emitting diodes with a P-type surface bonded to a transparent submount to increase light extraction efficiency
Usefulness: Light emitting diodes with a P-type surface bonded to a transparent submount to increase light extraction efficiency
Summary: Used as a light emitting device.
Novelty: Light emitting device comprises a LED structure comprised of an active layer positioned between positive and negative type layers, and a transparent sub-mount material bonded to a first surface of the structure using transparent glue layer

Industry

Optics

Sub Category

LED/OLED

Application No.

8124991

Others

Background

The LED structure affects how much light is emitted. In order to increase the light output power from the front side of the LED, conventional LEDs are typically equipped with a mirror placed on the backside of the substrate, or a mirror coating on the lead frame. However, this reflected light is re-absorbed by the active region of the LED, because the photon energy of emitted light is almost same as the band-gap energy of the light emitting materials. Due to this re-absorption of the emitted light by the active region, the net output power or the efficiency of the LED is decreased.  Therefore, to achieve highly output power efficiency of the LED, device structures in which re-absorption of the light is minimized are desirable.

Additional Technologies by these Inventors

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• Improved Manufacturing of Semiconductor Lasers
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• Growth of High-Quality, Thick, Non-Polar M-Plane GaN Films
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• Growth of Planar Semi-Polar Gallium Nitride
• Defect Reduction of Non-Polar and Semi-Polar III-Nitrides
• MOCVD Growth of Planar Non-Polar M-Plane Gallium Nitride
• Lateral Growth Method for Defect Reduction of Semipolar Nitride Films
• Low Temperature Deposition of Magnesium Doped Nitride Films
• Growth of Polyhedron-Shaped Gallium Nitride Bulk Crystals
• Improved Manufacturing of Solid State Lasers via Patterning of Photonic Crystals
• Control of Photoelectrochemical (PEC) Etching by Modification of the Local Electrochemical Potential of the Semiconductor Structure
• Phosphor-Free White Light Source
• Single or Multi-Color High Efficiency LED by Growth Over a Patterned Substrate
• High Efficiency LED with Optimized Photonic Crystal Extractor
• Packaging Technique for the Fabrication of Polarized Light Emitting Diodes
• (In,Ga,Al)N Optoelectronic Devices with Thicker Active Layers for Improved Performance
• Oxyfluoride Phosphors for Use in White Light LEDs
• III-V Nitride Device Structures on Patterned Substrates
• Growth of Semipolar III-V Nitride Films with Lower Defect Density
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• Highly Efficient Blue-Violet III-Nitride Semipolar Laser Diodes
• Method for Manufacturing Improved III-Nitride LEDs and Laser Diodes: Monolithic Integration of Optically Pumped and Electrically Injected III-Nitride LEDs
• Defect Reduction in GaN films using in-situ SiNx Nanomask
• Semi-polar LED/LD Devices on Relaxed Template with Misfit Dislocation at Hetero-interface
• Limiting Strain-Relaxation in III-Nitride Heterostructures by Substrate Patterning
• Suppression of Defect Formation and Increase in Critical Thickness by Silicon Doping
• High Efficiency Semipolar AlGaN-Cladding-Free Laser Diodes
• Low-Cost Zinc Oxide for High-Power-Output, GaN-Based LEDs (UC Case 2010-183)
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• Method for Increasing GaN Substrate Area in Nitride Devices
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• Optimization of Laser Bar Orientation for Nonpolar Laser Diodes
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• Low-Droop LED Structure on GaN Semi-polar Substrates
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• Technique for the Nitride Growth of Semipolar Thin Films, Heterostructures, and Semiconductor Devices
• Planar, Nonpolar M-Plane III-Nitride Films Grown on Miscut Substrates
• High-Efficiency, Mirrorless Non-Polar and Semi-Polar Light Emitting Devices
• High Light Extraction Efficiency III-Nitride LED
• Tunable White Light Based on Polarization-Sensitive LEDs
• Method for Improved Surface of (Ga,Al,In,B)N Films on Nonpolar or Semipolar Subtrates
• Improved Anisotropic Strain Control in Semipolar Nitride Devices
• III-Nitride Tunnel Junction with Modified Interface
• Enhanced Light Extraction LED with a Tunnel Junction Contact Wafer Bonded to a Conductive Oxide
• Increased Light Extraction with Multistep Deposition of ZnO on GaN
• Hybrid Growth Method for Improved III-Nitride Tunnel Junction Devices
• Contact Architectures for Tunnel Junction Devices
• New Blue Phosphor for High Heat Applications
• Internal Heating for Ammonothermal Growth of Group-III Nitride Crystals
• Methods for Fabricating III-Nitride Tunnel Junction Devices
• Multifaceted III-Nitride Surface-Emitting Laser
• Laser Diode System For Horticultural Lighting
• Fabricating Nitride Layers
• Reduction in Leakage Current and Increase in Efficiency of III-Nitride MicroLEDS
• Vertical Cavity Surface-Emitting Lasers with Continuous Wave Operation
• Laser Lighting System Incorporating an Additional Scattered Laser

Tech ID/UC Case

22796/2007-670-0

Related Cases

2007-670-0

*Abstract

A III-nitride light emitting diode (LED), in which light can be extracted from two surfaces of the LED before entering a shaped optical element and subsequently being extracted to air.

*Applications

• LED manufacturing   

*IP Issue Date

Feb 28, 2012

*Principal Investigator

Name: Hirokuni Asamizu

Department:

Name: Steven DenBaars

Department:

Name: Kenji Iso

Department:

Name: Shuji Nakamura

Department:

Name: Makoto Saito

Department:

Name: Hitoshi Sato

Department:

Country/Region

USA