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).

  • Patent number: 9349910
    Abstract: 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: Grant
    Filed: January 30, 2014
    Date of Patent: May 24, 2016
    Assignee: Lehigh University
    Inventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee, Hongping Zhao
  • Publication number: 20140191189
    Abstract: 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: Application
    Filed: January 30, 2014
    Publication date: July 10, 2014
    Applicant: LEHIGH UNIVERSITY
    Inventors: Nelson TANSU, Ronald A. ARIF, Yik Khoon EE, Hongping ZHAO
  • Patent number: 8659005
    Abstract: 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: Grant
    Filed: December 24, 2007
    Date of Patent: February 25, 2014
    Assignee: Lehigh University
    Inventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee, Hongping Zhao
  • Patent number: 8586963
    Abstract: 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: Grant
    Filed: December 8, 2010
    Date of Patent: November 19, 2013
    Assignee: Lehigh University
    Inventors: Nelson Tansu, James F. Gilchrist, Yik-Khoon Ee, Pisist Kumnorkaew
  • Patent number: 8541252
    Abstract: 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: Grant
    Filed: December 17, 2010
    Date of Patent: September 24, 2013
    Assignee: Lehigh University
    Inventors: Nelson Tansu, Helen M. Chan, Richard P. Vinci, Yik-Khoon Ee, Jeffrey Biser
  • Patent number: 8076667
    Abstract: 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: Grant
    Filed: December 24, 2007
    Date of Patent: December 13, 2011
    Assignee: Lehigh University
    Inventors: Nelson Tansu, Yik Khoon Ee, James F. Gilchrist, Pisit Kumnorkaew, Ronald A. Arif
  • Patent number: 8030641
    Abstract: 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: Grant
    Filed: December 19, 2007
    Date of Patent: October 4, 2011
    Assignee: Lehigh University
    Inventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee
  • Publication number: 20110155999
    Abstract: 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: Application
    Filed: December 8, 2010
    Publication date: June 30, 2011
    Applicant: Lehigh University
    Inventors: Nelson Tansu, James F. Gilchrist, Yik-Khoon Ee, Pisist Kumnorkaew
  • Publication number: 20110147703
    Abstract: 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: Application
    Filed: December 17, 2010
    Publication date: June 23, 2011
    Applicant: LEHIGH UNIVERSITY
    Inventors: Nelson Tansu, Helen M. Chan, Richard P. Vinci, Yik-Khoon Ee, Jeffrey Biser
  • Publication number: 20100327783
    Abstract: A light emitting device comprising a staggered composition quantum well.
    Type: Application
    Filed: December 24, 2007
    Publication date: December 30, 2010
    Applicant: LEHIGH UNIVERSITY
    Inventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee, Hongping Zhao
  • Patent number: 7842531
    Abstract: 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: Grant
    Filed: March 5, 2009
    Date of Patent: November 30, 2010
    Assignee: Lehigh University
    Inventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee
  • Publication number: 20090315013
    Abstract: 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: Application
    Filed: December 24, 2007
    Publication date: December 24, 2009
    Applicant: LEHIGH UNIVERSITY
    Inventors: Nelson Tansu, Yik Khoon Ee, James F. Gilchrist, Pisit Kumnorkaew, Ronald A. Arif
  • Publication number: 20090162963
    Abstract: 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: Application
    Filed: March 5, 2009
    Publication date: June 25, 2009
    Applicant: LEHIGH UNIVERSITY
    Inventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee
  • Patent number: 7518139
    Abstract: 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: Grant
    Filed: October 31, 2006
    Date of Patent: April 14, 2009
    Assignee: Lehigh University
    Inventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee
  • Publication number: 20080144685
    Abstract: 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: Application
    Filed: December 19, 2007
    Publication date: June 19, 2008
    Inventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee
  • Publication number: 20080099755
    Abstract: 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: Application
    Filed: October 31, 2006
    Publication date: May 1, 2008
    Applicant: Lehigh University
    Inventors: Nelson Tansu, Ronald A. Arif, Yik Khoon Ee