Suigen, South Korea
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Patent
Tohoku Techno Arch Co., Furukawa Electric Group, Mitsubishi Group, EpiValley Co., Wavesquare Inc. and Dowa Holdings Co. | Date: 2010-08-18

A GaN-based thin film (thick film) is grown using a metal buffer layer grown on a substrate. (a) A metal buffer layer (210) made of, for example, Cr or Cu is vapor-deposited on a sapphire substrate (120). (b) A substrate obtained by vapor-depositing the metal buffer layer (210) on the sapphire substrate (120) is nitrided in an ammonia gas ambient, thereby forming a metal nitride layer (212). (c) A GaN buffer layer (222) is grown on the nitrided metal buffer layers (210, 212). (d) Finally, a GaN single-crystal layer (220) is grown. This GaN single-crystal layer (220) can be grown to have various thicknesses depending on the objects. A freestanding substrate can be fabricated by selective chemical etching of the substrate fabricated by the above steps. It is also possible to use the substrate fabricated by the above steps as a GaN template substrate for fabricating a GaN-based light emitting diode or laser diode.


Patent
Tohoku Techno Arch Co., Furukawa Electric Group, Mitsubishi Group, DOWA Holdings Co., EpiValley Co. and Wavesquare Inc. | Date: 2010-06-02

A GaN-based thin film (thick film) is grown using a metal buffer layer grown on a substrate. (a) A metal buffer layer (210) made of, for example, Cr or Cu is vapor-deposited on a sapphire substrate (120). (b) A substrate obtained by vapor-depositing the metal buffer layer (210) on the sapphire substrate (120) is nitrided in an ammonia gas ambient, thereby forming a metal nitride layer (212). (c) A GaN buffer layer (222) is grown on the nitrided metal buffer layers (210, 212). (d) Finally, a GaN single-crystal layer (220) is grown. This Gan single-crystal layer (220) can be grown to have various thicknesses depending on the objects. A freestanding substrate can be fabricated by selective chemical etching of the substrate fabricated by the above steps. It is also possible to use the substrate fabricated by the above steps as a GaN template substrate for fabricating a GaN-based light emitting diode or laser diode.


Patent
Tohoku Techno Arch Co., Furukawa Electric Group, Mitsubishi Group, DOWA Holdings Co., EpiValley Co. and Wavesquare Inc. | Date: 2010-06-16

A GaN-based thin film (thick film) is grown using a metal buffer layer grown on a substrate. (a) A metal buffer layer (210) made of, for example, Cr or Cu is vapor-deposited on a sapphire substrate (120). (b) A substrate obtained by vapor-depositing the metal buffer layer (210) on the sapphire substrate (120) is nitrided in an ammonia gas ambient, thereby forming a metal nitride layer (212) (c) A GaN buffer layer (222) is grown on the nitrided metal buffer layers (210, 212). (d) Finally, a GaN single-crystal layer (220) is grown. This GaN single-crystal layer (220) can be grown to have various thicknesses depending on the objects. A freestanding substrate can be fabricated by selective chemical etching of the substrate fabricated by the above steps. It is also possible to use the substrate fabricated by the above steps as a GaN template substrate for fabricating a GaN-based light emitting diode or laser diode.


Patent
Tohoku Techno Arch Co., Furukawa Electric Group, Mitsubishi Group, DOWA Holdings Co., EpiValley Co. and Wavesquare Inc. | Date: 2010-07-07

A GaN-based thin film (thick film) is grown using a metal buffer layer grown on a substrate. (a) A metal buffer layer (210) made of, for example, Cr or Cu is vapor-deposited on a sapphire substrate (120). (b) A substrate obtained by vapor-depositing the metal buffer layer (210) on the sapphire substrate (120) is nitrided in an ammonia gas ambient, thereby forming a metal nitride layer (212). (c) A GaN buffer layer (222) is grown on the nitrided metal buffer layers (210, 212). (d) Finally, a GaN single-crystal layer (220) is grown. This GaN single-crystal layer (220) can be grown to have various thicknesses depending on the objects. A freestanding substrate can be fabricated by selective chemical etching of the substrate fabricated by the above steps. It is also possible to use the substrate fabricated by the above steps as a GaN template substrate for fabricating a GaN-based light emitting diode or laser diode.


Patent
Tohoku Techno Arch Co., Furukawa Electric Group, Mitsubishi Group, DOWA Holdings Co., Wavesquare Inc. and EpiValley Co. | Date: 2010-06-02

A GaN-based thin film (thick film) is grown using a metal buffer layer grown on a substrate, (a) A metal buffer layer (210) made of, for example, Cr or Cu is vapor-deposited on a sapphire substrate (120). (b) A substrate obtained by vapor-depositing the metal buffer layer (210) on the sapphire substrate (120) is nitrided in an ammonia gas ambient, thereby forming a metal nitride layer (212), (c) A GaN buffer layer (222) is grown on the nitrided metal buffer layers (210, 212), (d) Finally, a GaN single-crystal layer (220) is grown. This GaN single-crystal layer (220) can be grown to have various thicknesses depending on the objects. A freestanding substrate can be fabricated by selective chemical etching of the substrate fabricated the above steps. It is also possible to use the substrate fabricated by the above steps as a GaN template substrate for fabricating a Gan-based light emitting diode or laser diode.


Patent
Tohoku Techno Arch Co., Furukawa Electric Group, Mitsubishi Group, DOWA Holdings Co., EpiValley Co. and Wavesquare Inc. | Date: 2010-06-16

A GaN-based thin film (thick film) is grown using a metal buffer layer grown on a substrate. (a) A metal buffer layer (210) made of, for example, Cr or Cu is vapor-deposited on a sapphire substrate (120). (b) A substrate obtained by vapor-depositing the metal buffer layer (210) on the sapphire substrate (120) is nitrided in an ammonia gas ambient, thereby forming a metal nitride layer (212). (c) A GaN buffer layer (222) is grown on the nitrided metal buffer layers (210, 212). (d) Finally, a GaN single-crystal layer (220) is grown. This GaN single-crystal layer (220) can be grown to have various thicknesses depending on the objects. A freestanding substrate can be fabricated by selective chemical etching of the substrate fabricated by the above steps. It is also possible to use the substrate fabricated by the above steps as a GaN template substrate for fabricating a GaN-based light emitting diode or laser diode.


Patent
Tohoku Techno Arch Co., Furukawa Electric Group, Mitsubishi Group, Dowa Holdings Co., EpiValley Co. and Wavesquare Inc. | Date: 2010-06-09

A GaN-based thin film (thick film) is grown using a metal buffer layer grown on a substrate. (a) A metal buffer layer (210) made of, for example, Cr or Cu is vapor-deposited on a sapphire substrate (120). (b) A substrate obtained by vapor-depositing the metal buffer layer (210) on the sapphire substrate (120) is nitrided in an ammonia gas ambient, thereby forming a metal nitride layer (212). (c) A GaN buffer layer (222) is grown on the nitrided metal buffer layers (210, 212). (d) Finally, a GaN single-crystal layer (220) is grown. This GaN single-crystal layer (220) can be grown to have various thicknesses depending on the objects. A freestanding substrate can be fabricated by selective chemical etching of the substrate fabricated by the above steps. It is also possible to use the substrate fabricated by the above steps as a GaN template substrate for fabricating a GaN-based light emitting diode or laser diode.


Ryu H.-Y.,Inha University | Shim J.-I.,Hanyang University | Kim C.-H.,EpiValley Co. | Choi J.H.,EpiValley Co. | And 4 more authors.
IEEE Photonics Technology Letters | Year: 2011

The authors investigate efficiency and electron leakage characteristics in GaN-based light-emitting diodes (LEDs) without AlGaN electron-blocking-layer (EBL) structures. Both simulation and electroluminescence (EL) measurement results show that the internal quantum efficiency decreases rapidly as the thickness of an undoped GaN interlayer between active layers and a p-GaN layer increases, which is caused by electron leakage from active layers to the p-GaN due to inefficient hole injection. However, photoluminescence (PL) measurement results show that the quality of active layers deteriorates as the interlayer thickness decreases. The EL and PL results imply that the optimization of the undoped GaN interlayer thickness is important for achieving high internal quantum efficiency in AlGaN-EBL-free LEDs. © 2011 IEEE.


Patent
Epivalley Co. | Date: 2010-08-02

The present disclosure provides a dimming control method for a display having a light-emitting device which includes: a first light-emitting body including an active layer generating a first light by recombination of electrons and holes; and a second light-emitting body excited by the first light and emitting a second light having a longer wavelength than the first light, the dimming control method including: controlling the power which will be supplied to the light-emitting device according to a dimming request; and adjusting the brightness of the display according to the controlled power using the second light-emitting body containing a first fluorescent material having a characteristic that chromaticity coordinates are shifted in a first direction according to the power control and a second fluorescent material having a characteristic that chromaticity coordinates are shifted in a second direction opposite to the first direction according to the power control.

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