Patents by Inventor Yik Khoon Ee
Yik Khoon Ee has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9349910Abstract: A light emitting device comprising a staggered composition quantum well (QW) has a step-function-like profile in the QW, which provides higher radiative efficiency and optical gain by providing improved electron-hole wavefunction overlap. The staggered QW includes adjacent layers having distinctly different compositions. The staggered QW has adjacent layers Xn, wherein X is a quantum well component and in one quantum well layer n is a material composition selected for emission at a first target light regime, and in at least one other quantum well layer n is a distinctly different composition for emission at a different target light regime. X may be an In-content layer and the multiple Xn-containing layers provide a step function In-content profile.Type: GrantFiled: January 30, 2014Date of Patent: May 24, 2016Assignee: Lehigh UniversityInventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee, Hongping Zhao
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Publication number: 20140191189Abstract: A light emitting device comprising a staggered composition quantum well (QW) has a step-function-like profile in the QW, which provides higher radiative efficiency and optical gain by providing improved electron-hole wavefunction overlap. The staggered QW includes adjacent layers having distinctly different compositions. The staggered QW has adjacent layers Xn, wherein X is a quantum well component and in one quantum well layer n is a material composition selected for emission at a first target light regime, and in at least one other quantum well layer n is a distinctly different composition for emission at a different target light regime. X may be an In-content layer and the multiple Xn-containing layers provide a step function In-content profile.Type: ApplicationFiled: January 30, 2014Publication date: July 10, 2014Applicant: LEHIGH UNIVERSITYInventors: Nelson TANSU, Ronald A. ARIF, Yik Khoon EE, Hongping ZHAO
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Patent number: 8659005Abstract: A light emitting device comprising a staggered composition quantum well (QW) has a step-function-like profile in the QW, which provides higher radiative efficiency and optical gain by providing improved electron-hole wavefunction overlap. The staggered QW includes adjacent layers having distinctly different compositions. The staggered QW has adjacent layers Xn wherein X is a quantum well component and in one quantum well layer n is a material composition selected for emission at a first target light regime, and in at least one other quantum well layer n is a distinctly different composition for emission at a different target light regime. X may be an In-content layer and the multiple Xn-containing a step function In-content profile.Type: GrantFiled: December 24, 2007Date of Patent: February 25, 2014Assignee: Lehigh UniversityInventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee, Hongping Zhao
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Patent number: 8586963Abstract: A conventional semiconductor LED is modified to include a microlens layer over its light-emitting surface. The LED may have an active layer including at least one quantum well layer of InGaN and GaN. The microlens layer includes a plurality of concave microstructures that cause light rays emanating from the LED to diffuse outwardly, leading to an increase in the light extraction efficiency of the LED. The concave microstructures may be arranged in a substantially uniform array, such as a close-packed hexagonal array. The microlens layer is preferably constructed of curable material, such as polydimethylsiloxane (PDMS), and is formed by soft-lithography imprinting by contacting fluid material of the microlens layer with a template bearing a monolayer of homogeneous microsphere crystals, to cause concave impressions, and then curing the material to fix the concave microstructures in the microlens layer and provide relatively uniform surface roughness.Type: GrantFiled: December 8, 2010Date of Patent: November 19, 2013Assignee: Lehigh UniversityInventors: Nelson Tansu, James F. Gilchrist, Yik-Khoon Ee, Pisist Kumnorkaew
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Patent number: 8541252Abstract: The use of an abbreviated GaN growth mode on nano-patterned AGOG sapphire substrates, which utilizes a process of using 15 nm low temperature GaN buffer and bypassing etch-back and recovery processes during epitaxy, enables the growth of high-quality GaN template on nano-patterned AGOG sapphire. The GaN template grown on nano-patterned AGOG sapphire by employing abbreviated growth mode has two orders of magnitude lower threading dislocation density than that of conventional GaN template grown on planar sapphire. The use of abbreviated growth mode also leads to significant reduction in cost of the epitaxy. The growths and characteristics of InGaN quantum wells (QWs) light emitting diodes (LEDs) on both templates were compared. The InGaN QWs LEDs grown on the nano-patterned AGOG sapphire demonstrated at least a 24% enhancement of output power enhancement over that of LEDs grown on conventional GaN templates.Type: GrantFiled: December 17, 2010Date of Patent: September 24, 2013Assignee: Lehigh UniversityInventors: Nelson Tansu, Helen M. Chan, Richard P. Vinci, Yik-Khoon Ee, Jeffrey Biser
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Patent number: 8076667Abstract: A tight emitting device comprises at least one p-type layer and at least one n-type layer and a microlens array surface. A method for improving light efficiency of a light emitting device, comprises depositing polystyrene microspheres by rapid convection deposition on surface of light emitting device; depositing a monolayer of close-packed SIO2 microspheres onto the polystyrene microspheres; and heal treating to convert the polystyrene microspheres into a planar microlayer film to provide a surface comprising substantially two-dimensional (2D) hexagonal close-packed SIO2 colloidal microsphere crystals partially imposed into a polystyrene monolayer film.Type: GrantFiled: December 24, 2007Date of Patent: December 13, 2011Assignee: Lehigh UniversityInventors: Nelson Tansu, Yik Khoon Ee, James F. Gilchrist, Pisit Kumnorkaew, Ronald A. Arif
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Patent number: 8030641Abstract: A gallium nitride-based device has ? first GaN layer and ? type II quantum well active region over the GaN layer. The type II quantum well active region comprises at least one InGaN layer and at least one GaNAs layer, wherein the InGaN comprises ? graded molar In concentration.Type: GrantFiled: December 19, 2007Date of Patent: October 4, 2011Assignee: Lehigh UniversityInventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee
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Publication number: 20110155999Abstract: A conventional semiconductor LED is modified to include a microlenslayer over its light-emitting surface. The LED may have an active layer including at least one quantum well layer of InGaN and GaN. The microlens layer includes a plurality of concave microstructures that cause light rays emanating from the LED to diffuse outwardly, leading to an increase in the light extraction efficiency of the LED. The concave microstructures may be arranged in a substantially uniform array, such as a close-packed hexagonal array. The microlens layer is preferably constructed of curable material, such as polydimethylsiloxane (PDMS), and is formed by soft-lithography imprinting by contacting fluid material of the microlens layer with a template bearing a monolayer of homogeneous microsphere crystals, to cause concave impressions, and then curing the material to fix the concave microstructures in the microlens layer and provide relatively uniform surface roughness.Type: ApplicationFiled: December 8, 2010Publication date: June 30, 2011Applicant: Lehigh UniversityInventors: Nelson Tansu, James F. Gilchrist, Yik-Khoon Ee, Pisist Kumnorkaew
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Publication number: 20110147703Abstract: The use of an abbreviated GaN growth mode on nano-patterned AGOG sapphire substrates, which utilizes a process of using 15 nm low temperature GaN buffer and bypassing etch-back and recovery processes during epitaxy, enables the growth of high-quality GaN template on nano-patterned AGOG sapphire. The GaN template grown on nano-patterned AGOG sapphire by employing abbreviated growth mode has two orders of magnitude lower threading dislocation density than that of conventional GaN template grown on planar sapphire. The use of abbreviated growth mode also leads to significant reduction in cost of the epitaxy. The growths and characteristics of InGaN quantum wells (QWs) light emitting diodes (LEDs) on both templates were compared. The InGaN QWs LEDs grown on the nano-patterned AGOG sapphire demonstrated at least a 24% enhancement of output power enhancement over that of LEDs grown on conventional GaN templates.Type: ApplicationFiled: December 17, 2010Publication date: June 23, 2011Applicant: LEHIGH UNIVERSITYInventors: Nelson Tansu, Helen M. Chan, Richard P. Vinci, Yik-Khoon Ee, Jeffrey Biser
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Publication number: 20100327783Abstract: A light emitting device comprising a staggered composition quantum well.Type: ApplicationFiled: December 24, 2007Publication date: December 30, 2010Applicant: LEHIGH UNIVERSITYInventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee, Hongping Zhao
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Patent number: 7842531Abstract: A gallium nitride-based device has a first GaN layer and a type II quantum well active region over the GaN layer. The type II quantum well active region comprises at least one InGaN layer and at least one GaNAs layer comprising 1.5 to 8% As concentration. The type II quantum well emits in the 400 to 700 nm region with reduced polarization affect.Type: GrantFiled: March 5, 2009Date of Patent: November 30, 2010Assignee: Lehigh UniversityInventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee
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Publication number: 20090315013Abstract: A tight emitting device comprises at least one p-type layer and at least one n-type layer and a microlens array surface. A method for improving light efficiency of a light emitting device, comprises depositing polystyrene microspheres by rapid convection deposition on surface of light emitting device; depositing a monolayer of close-packed SIO2 microspheres onto the polystyrene microspheres; and heal treating to convert the polystyrene microspheres into a planar microlayer film to provide a surface comprising substantially two-dimensional (2D) hexagonal close-packed S1O2 colloidal microsphere crystals partially imposed into a polystyrene monolayer film.Type: ApplicationFiled: December 24, 2007Publication date: December 24, 2009Applicant: LEHIGH UNIVERSITYInventors: Nelson Tansu, Yik Khoon Ee, James F. Gilchrist, Pisit Kumnorkaew, Ronald A. Arif
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Publication number: 20090162963Abstract: A gallium nitride-based device has a first GaN layer and a type II quantum well active region over the GaN layer. The type II quantum well active region comprises at least one InGaN layer and at least one GaNAs layer comprising 1.5 to 8% As concentration. The type II quantum well emits in the 400 to 700 nm region with reduced polarization affect.Type: ApplicationFiled: March 5, 2009Publication date: June 25, 2009Applicant: LEHIGH UNIVERSITYInventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee
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Patent number: 7518139Abstract: A gallium nitride-based device has a first GaN layer and a type II quantum well active region over the GaN layer. The type II quantum well active region comprises at least one InGaN layer and at least one GaNAs layer comprising 1.5 to 8% As concentration. The type II quantum well emits in the 400 to 700 nm region with reduced polarization affect.Type: GrantFiled: October 31, 2006Date of Patent: April 14, 2009Assignee: Lehigh UniversityInventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee
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Publication number: 20080144685Abstract: A gallium nitride-based device has a first GaN layer and a type II quantum well active region over the GaN layer. The type II quantum well active region comprises at least one InGaN layer and at least one GaNAs layer, wherein the InGaN comprises a graded molar In concentration.Type: ApplicationFiled: December 19, 2007Publication date: June 19, 2008Inventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee
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Publication number: 20080099755Abstract: A gallium nitride-based device has a first GaN layer and a type II quantum well active region over the GaN layer. The type II quantum well active region comprises at least one InGaN layer and at least one GaNAs layer comprising 1.5 to 8% As concentration. The type II quantum well emits in the 400 to 700 nm region with reduced polarization affect.Type: ApplicationFiled: October 31, 2006Publication date: May 1, 2008Applicant: Lehigh UniversityInventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee