Patents by Inventor Steven P. Denbaars

Steven P. Denbaars 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: 10297721
    Abstract: A method for fabricating a Zinc Oxide (ZnO) conductive film on a semiconductor material, including depositing a doped ZnO seed layer on a diode, wherein the ZnO seed layer forms an electrical contact to the diode; and depositing a ZnO layer on the ZnO seed layer, wherein the ZnO seed layer and the ZnO layer each have a thickness, a crystal quality, and a doping level such that (1) the diode comprising III-nitride material is turned on with a turn on voltage of 2.75 volts or less applied across the ZnO layers and the diode, and (2) a contact resistance, of a structure comprising the ZnO layers and the diode, is lower as compared to a contact resistance of a structure comprising the ZnO layer directly on the diode without the ZnO seed layer.
    Type: Grant
    Filed: February 28, 2018
    Date of Patent: May 21, 2019
    Assignee: The Regents of the University of California
    Inventors: Asad J. Mughal, Sang Ho Oh, Steven P. DenBaars
  • Publication number: 20190074404
    Abstract: A hybrid growth method for III-nitride tunnel junction devices uses metal-organic chemical vapor deposition (MOCVD) to grow one or more light-emitting or light-absorbing structures and ammonia-assisted or plasma-assisted molecular beam epitaxy (MBE) to grow one or more tunnel junctions. Unlike p-type gallium nitride (p-GaN) grown by MOCVD, p-GaN grown by MBE is conductive as grown, which allows for its use in a tunnel junction. Moreover, the doping limits of MBE materials are higher than MOCVD materials. The tunnel junctions can be used to incorporate multiple active regions into a single device. In addition, n-type GaN (n-GaN) can be used as a current spreading layer on both sides of the device, eliminating the need for a transparent conductive oxide (TCO) layer or a silver (Au) mirror.
    Type: Application
    Filed: July 11, 2016
    Publication date: March 7, 2019
    Applicant: The Regents of the University of California
    Inventors: Erin C. Young, Benjamin P. Yonkee, John T. Leonard, Tal Margalith, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • Patent number: 10217916
    Abstract: A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.
    Type: Grant
    Filed: August 15, 2014
    Date of Patent: February 26, 2019
    Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Shuji Nakamura, Steven P. DenBaars, Hirokuni Asamizu
  • Patent number: 10205300
    Abstract: Laser dazzler devices and methods of using laser dazzler devices are disclosed. More specifically, embodiments of the present invention provide laser dazzling devices power by one or more green laser diodes characterized by a wavelength of about 500 nm to 540 nm. In various embodiments, laser dazzling devices according to the present invention include non-polar and/or semi-polar green laser diodes. In a specific embodiment, a laser dazzling device includes a plurality of green laser diodes.
    Type: Grant
    Filed: December 30, 2015
    Date of Patent: February 12, 2019
    Inventors: James W. Raring, Paul Rudy, Vinod Khosla, Pierre Lamond, Steven P. Denbaars, Shuji Nakamura, Richard T. Ogawa
  • Publication number: 20180374699
    Abstract: A III-nitride tunnel junction with a modified p-n interface, wherein the modified p-n interface includes a delta-doped layer to reduce tunneling resistance. The delta-doped layer may be doped using donor atoms comprised of Oxygen (O), Germanium (Ge) or Silicon (Si); acceptor atoms comprised of Magnesium (Mg) or Zinc (Zn); or impurities comprised of Iron (Fe) or Carbon (C).
    Type: Application
    Filed: November 1, 2016
    Publication date: December 27, 2018
    Applicant: The Regents of the University of California
    Inventors: Benjamin P. Yonkee, Erin C. Young, John T. Leonard, Tal Margalith, James S. Speck, Steven P. DenBaars, Shuji Nakamura
  • Publication number: 20180190875
    Abstract: A method for fabricating a Zinc Oxide (ZnO) conductive film on a semiconductor material, including depositing a doped ZnO seed layer on a diode, wherein the ZnO seed layer forms an electrical contact to the diode; and depositing a ZnO layer on the ZnO seed layer, wherein the ZnO seed layer and the ZnO layer each have a thickness, a crystal quality, and a doping level such that (1) the diode comprising III-nitride material is turned on with a turn on voltage of 2.75 volts or less applied across the ZnO layers and the diode, and (2) a contact resistance, of a structure comprising the ZnO layers and the diode, is lower as compared to a contact resistance of a structure comprising the ZnO layer directly on the diode without the ZnO seed layer.
    Type: Application
    Filed: February 28, 2018
    Publication date: July 5, 2018
    Applicant: The Regents of the University of California
    Inventors: Asad J. Mughal, Sang Ho Oh, Steven P. DenBaars
  • Publication number: 20180152004
    Abstract: An optoelectronic device grown on a miscut of GaN, wherein the miscut comprises a semi-polar GaN crystal plane (of the GaN) miscut x degrees from an m-plane of the GaN and in a c-direction of the GaN, where ?15<x<?1 and 1<x<15 degrees.
    Type: Application
    Filed: January 26, 2018
    Publication date: May 31, 2018
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Po Shan Hsu, Kathryn M. Kelchner, Robert M. Farrell, Daniel A. Haeger, Hiroaki Ohta, Anurag Tyagi, Shuji Nakamura, Steven P. DenBaars, James S. Speck
  • Patent number: 9951912
    Abstract: A lighting apparatus for emitting polarized white light, which includes at least a first light source for emitting primary light comprised of one or more first wavelengths and having a first polarization direction; and at least a second light source for emitting secondary light in the first polarization direction, comprised of one or more secondary wavelengths, wherein the first light and the secondary light are combined to produce a polarized white light. The lighting apparatus may further comprise a polarizer for controlling the primary light's intensity, wherein a rotation of the polarizer varies an alignment of its polarization axis with respect to the first polarization direction, which varies transmission of the primary light through the polarizer, which controls a color co-ordinate or hue of the white light.
    Type: Grant
    Filed: December 11, 2014
    Date of Patent: April 24, 2018
    Assignee: The Regents of the University of California
    Inventors: Natalie Fellows DeMille, Hisashi Masui, Steven P. DenBaars, Shuji Nakamura
  • Patent number: 9935243
    Abstract: A method for fabricating a Zinc Oxide (ZnO) conductive film on a semiconductor material, including depositing a doped ZnO seed layer on a diode, wherein the ZnO seed layer forms an electrical contact to the diode; and depositing a ZnO layer on the ZnO seed layer, wherein the ZnO seed layer and the ZnO layer each have a thickness, a crystal quality, and a doping level such that (1) the diode comprising III-nitride material is turned on with a turn on voltage of 2.75 volts or less applied across the ZnO layers and the diode, and (2) a contact resistance, of a structure comprising the ZnO layers and the diode, is lower as compared to a contact resistance of a structure comprising the ZnO layer directly on the diode without the ZnO seed layer.
    Type: Grant
    Filed: September 15, 2016
    Date of Patent: April 3, 2018
    Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Asad J. Mughal, Sang Ho Oh, Steven P. DenBaars
  • Patent number: 9927076
    Abstract: A high-power, high-brightness lighting system for large venue lighting, which includes a laser diode as the excitation source and one or more phosphor materials placed at a remote distance from the laser source. The invention offers a lighting system with the advantages of high brightness, high efficiency, high luminous efficacy, long lifetimes, quick turn-on times, suitable color properties, environmental sustainability, and easy maintenance, which may allow for smart and flexible control over large area lighting systems with resulting savings in operating and maintenance costs.
    Type: Grant
    Filed: January 23, 2017
    Date of Patent: March 27, 2018
    Assignee: The Regents of the University of California
    Inventors: Kristin A. Denault, Steven P. DenBaars, Ram Seshadri Seshadri
  • Patent number: 9917422
    Abstract: An optoelectronic device grown on a miscut of GaN, wherein the miscut comprises a semi-polar GaN crystal plane (of the GaN) miscut x degrees from an m-plane of the GaN and in a c-direction of the GaN, where ?15<x<?1 and 1<x<15 degrees.
    Type: Grant
    Filed: May 26, 2015
    Date of Patent: March 13, 2018
    Assignee: The Regents of the University of California
    Inventors: Po Shan Hsu, Kathryn M. Kelchner, Robert M. Farrell, Daniel A. Haeger, Hiroaki Ohta, Anurag Tyagi, Shuji Nakamura, Steven P. DenBaars, James S. Speck
  • Patent number: 9893236
    Abstract: A method of fabricating non-polar a-plane GaN/(Al,B,In,Ga)N multiple quantum wells (MQWs). The a-plane MQWs are grown on the appropriate GaN/sapphire template layers via metalorganic chemical vapor deposition (MOCVD) with well widths ranging from 20 ? to 70 ?. The room temperature photoluminescence (PL) emission energy from the a-plane MQWs followed a square well trend modeled using self-consistent Poisson-Schrodinger (SCPS) calculations. Optimal PL emission intensity is obtained at a quantum well width of 52 ? for the a-plane MQWs.
    Type: Grant
    Filed: October 23, 2015
    Date of Patent: February 13, 2018
    Assignees: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA, JAPAN SCIENCE AND TECHNOLOGY AGENCY
    Inventors: Michael D. Craven, Steven P. DenBaars
  • Publication number: 20180013035
    Abstract: A method for growth and fabrication of semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices, comprising identifying desired material properties for a particular device application, selecting a semipolar growth orientation based on the desired material properties, selecting a suitable substrate for growth of the selected semipolar growth orientation, growing a planar semipolar (Ga,Al,In,B)N template or nucleation layer on the substrate, and growing the semipolar (Ga,Al,In,B)N thin films, heterostructures or devices on the planar semipolar (Ga,Al,In,B)N template or nucleation layer. The method results in a large area of the semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices being parallel to the substrate surface.
    Type: Application
    Filed: September 7, 2017
    Publication date: January 11, 2018
    Applicants: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA, Japan Science and Technology Agency
    Inventors: Robert M. Farrell, JR., Troy J. Baker, Arpan Chakraborty, Benjamin A. Haskell, P. Morgan Pattison, Rajat Sharma, Umesh K. Mishra, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Patent number: 9859464
    Abstract: This invention is related to LED Light Extraction for optoelectronic applications. More particularly the invention relates to (Al, Ga, In)N combined with optimized optics and phosphor layer for highly efficient (Al, Ga, In)N based light emitting diodes applications, and its fabrication method. A further extension is the general combination of a shaped high refractive index light extraction material combined with a shaped optical element.
    Type: Grant
    Filed: December 23, 2015
    Date of Patent: January 2, 2018
    Assignee: The Regents of the University of California
    Inventors: Natalie Fellows DeMille, Steven P. DenBaars, Shuji Nakamura
  • Patent number: 9828695
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.
    Type: Grant
    Filed: April 20, 2016
    Date of Patent: November 28, 2017
    Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Asako Hirai, Zhongyuan Jia, Makoto Saito, Hisashi Yamada, Kenji Iso, Steven P. DenBaars, Shuji Nakamura, James S. Speck
  • Publication number: 20170327969
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate. The miscut angle towards the <000-1> direction is 0.75° or greater miscut and less than 27° miscut towards the <000-1> direction. Surface undulations are suppressed and may comprise faceted pyramids. A device fabricated using the film is also disclosed. A nonpolar III-nitride film having a smooth surface morphology fabricated using a method comprising selecting a miscut angle of a substrate upon which the nonpolar III-nitride films are grown in order to suppress surface undulations of the nonpolar III-nitride films. A nonpolar III-nitride-based device grown on a film having a smooth surface morphology grown on a miscut angle of a substrate which the nonpolar III-nitride films are grown. The miscut angle may also be selected to achieve long wavelength light emission from the nonpolar film.
    Type: Application
    Filed: May 26, 2017
    Publication date: November 16, 2017
    Applicant: The Regents of the University of California
    Inventors: Kenji Iso, Hisashi Yamada, Makoto Saito, Asako Hirai, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Patent number: 9793435
    Abstract: A method for growth and fabrication of semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices, comprising identifying desired material properties for a particular device application, selecting a semipolar growth orientation based on the desired material properties, selecting a suitable substrate for growth of the selected semipolar growth orientation, growing a planar semipolar (Ga,Al,In,B)N template or nucleation layer on the substrate, and growing the semipolar (Ga,Al,In,B)N thin films, heterostructures or devices on the planar semipolar (Ga,Al,In,B)N template or nucleation layer. The method results in a large area of the semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices being parallel to the substrate surface.
    Type: Grant
    Filed: November 30, 2015
    Date of Patent: October 17, 2017
    Assignees: The Regents of the University of California, Japan Science and Technology Agency
    Inventors: Robert M. Farrell, Jr., Troy J. Baker, Arpan Chakraborty, Benjamin A. Haskell, P. Morgan Pattison, Rajat Sharma, Umesh K. Mishra, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Patent number: 9773704
    Abstract: A method for the reuse of gallium nitride (GaN) epitaxial substrates uses band-gap-selective photoelectrochemical (PEC) etching to remove one or more epitaxial layers from bulk or free-standing GaN substrates without damaging the substrate, allowing the substrate to be reused for further growth of additional epitaxial layers. The method facilitates a significant cost reduction in device production by permitting the reuse of expensive bulk or free-standing GaN substrates.
    Type: Grant
    Filed: June 22, 2016
    Date of Patent: September 26, 2017
    Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Casey O. Holder, Daniel F. Feezell, Steven P. DenBaars, Shuji Nakamura
  • Publication number: 20170236807
    Abstract: III-V micro light-emitting diodes (LEDs) are fabricated using a photoelectrochemical (PEC) etch. A sacrificial layer and III-V device layers are epitaxially grown on a host substrate, wherein the III-V device layers are patterned to form the micro-LEDs. The sacrificial layer is removed by a photoelectrochemical (PEC) etch, so as to fully or partially separate the micro-LEDs from the substrate, before or after the micro-LEDs are bonded to a submount or intermediate substrate. The micro-LEDs may be bonded to a submount with a polymer film deposited thereon, wherein the polymer film with the micro-LEDs is subsequently delaminated from the submount. Alternatively, the intermediate substrate may be a transfer medium, wherein the micro-LEDs are separated from the host substrate by mechanical fracturing, and then bonded to a second substrate, after which the intermediate substrate is removed, wherein a third substrate may be bonded to exposed surfaces of the transferred micro-LEDs.
    Type: Application
    Filed: April 28, 2017
    Publication date: August 17, 2017
    Applicant: The Regents of the University of California
    Inventors: David Hwang, Nathan G. Young, Ben Yonkee, Burhan K. Saifaddin, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Patent number: 9653655
    Abstract: A method for fabricating a Light Emitting Diode (LED) with increased light extraction efficiency, comprising providing a III-Nitride based LED structure comprising a light emitting active layer between a p-type layer and an n-type layer; growing a Zinc Oxide (ZnO) layer epitaxially on the p-type layer by submerging a surface of the p-type layer in a low temperature aqueous solution, wherein the ZnO layer is a transparent current spreading layer; and depositing a p-type contact on the ZnO layer. The increase in efficiency may be more than 93% with very little or no increase in cost.
    Type: Grant
    Filed: November 3, 2010
    Date of Patent: May 16, 2017
    Assignee: The Regents of the University of California
    Inventors: Daniel B. Thompson, Jacob J. Richardson, Steven P. DenBaars, Jin Hyeok Kim, MaryAnn E. Lange