Patents by Inventor Naijuan Wu

Naijuan Wu 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: 9349947
    Abstract: An electric-pulse-induced-resistance change device (EPIR device) is provided which is a resistance switching device. It has a buffer layer inserted between a first active resistance switching layer and a second active resistance switching layer, with both active switching layers connected to electrode layers directly or through additional buffer layers between the active resistance switching layers and the electrodes. This device in its simplest form has the structure: electrode-active layer-buffer layer-active layer-electrode. The second active resistance switching layer may, in the alternative, be an ion donating layer, such that the structure becomes: electrode-active layer-buffer layer-ion donating layer-electrode. The EPIR device is constructed to mitigate the retention challenge.
    Type: Grant
    Filed: November 12, 2015
    Date of Patent: May 24, 2016
    Assignee: Board of Regents, University of Houston
    Inventors: Alex Ignatiev, Kristina Young-Fisher, Rabi Ebrahim, Naijuan Wu
  • Publication number: 20160064660
    Abstract: An electric-pulse-induced-resistance change device (EPIR device) is provided which is a resistance switching device. It has a buffer layer inserted between a first active resistance switching layer and a second active resistance switching layer, with both active switching layers connected to electrode layers directly or through additional buffer layers between the active resistance switching layers and the electrodes. This device in its simplest form has the structure: electrode-active layer-buffer layer-active layer-electrode. The second active resistance switching layer may, in the alternative, be an ion donating layer, such that the structure becomes: electrode-active layer-buffer layer-ion donating layer-electrode. The EPIR device is constructed to mitigate the retention challenge.
    Type: Application
    Filed: November 12, 2015
    Publication date: March 3, 2016
    Applicant: Board of Regents, University of Houston
    Inventors: Alex Ignatiev, Kristina Young-Fisher, Rabi Ebrahim, Naijuan Wu
  • Patent number: 9218901
    Abstract: An electric-pulse-induced-resistance change device (EPIR device) is provided which is a resistance switching device. It has a buffer layer inserted between a first active resistance switching layer and a second active resistance switching layer, with both active switching layers connected to electrode layers directly or through additional buffer layers between the active resistance switching layers and the electrodes. This device in its simplest form has the structure: electrode-active layer-buffer layer-active layer-electrode. The second active resistance switching layer may, in the alternative, be an ion donating layer, such that the structure becomes: electrode-active layer-buffer layer-ion donating layer-electrode. The EPIR device is constructed to mitigate the retention challenge.
    Type: Grant
    Filed: December 1, 2011
    Date of Patent: December 22, 2015
    Assignee: Board of Regents, University of Houston
    Inventors: Alex Ignatiev, Naijuan Wu, Kristina Young-Fisher, Rabi Ebrahim
  • Patent number: 8409879
    Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The selected duration of the electrical pulse is in the range of from about 8 nanosecond to about 100 milliseconds. The selected maximum value of the electrical pulse is in the range of from about 1 V to about 150 V. The electrical pulse may have square, saw-toothed, triangular, sine, oscillating or other waveforms, and may be of positive or negative polarity.
    Type: Grant
    Filed: May 23, 2011
    Date of Patent: April 2, 2013
    Assignee: Board of Regents, University of Houston
    Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
  • Publication number: 20120126195
    Abstract: An electric-pulse-induced-resistance change device (EPIR device) is provided which is a resistance switching device. It has a buffer layer inserted between a first active resistance switching layer and a second active resistance switching layer, with both active switching layers connected to electrode layers directly or through additional buffer layers between the active resistance switching layers and the electrodes. This device in its simplest form has the structure: electrode-active layer-buffer layer-active layer-electrode. The second active resistance switching layer may, in the alternative, be an ion donating layer, such that the structure becomes: electrode-active layer-buffer layer-ion donating layer-electrode. The EPIR device is constructed to mitigate the retention challenge.
    Type: Application
    Filed: December 1, 2011
    Publication date: May 24, 2012
    Inventors: Alex Ignatiev, Naijuan Wu, Kristina Young-Fisher, Rabi Ebrahim
  • Patent number: 8089111
    Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.
    Type: Grant
    Filed: September 17, 2009
    Date of Patent: January 3, 2012
    Assignee: Board of Regents, University of Houston
    Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
  • Publication number: 20110304423
    Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The selected duration of the electrical pulse is in the range of from about 8 nanosecond to about 100 milliseconds. The selected maximum value of the electrical pulse is in the range of from about 1 V to about 150 V. The electrical pulse may have square, saw-toothed, triangular, sine, oscillating or other waveforms, and may be of positive or negative polarity.
    Type: Application
    Filed: May 23, 2011
    Publication date: December 15, 2011
    Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
  • Patent number: 7955871
    Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.
    Type: Grant
    Filed: September 17, 2009
    Date of Patent: June 7, 2011
    Assignee: Board of Regents, University of Houston
    Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
  • Publication number: 20100134239
    Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.
    Type: Application
    Filed: September 17, 2009
    Publication date: June 3, 2010
    Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
  • Publication number: 20100014344
    Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.
    Type: Application
    Filed: September 17, 2009
    Publication date: January 21, 2010
    Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
  • Patent number: 7608467
    Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.
    Type: Grant
    Filed: January 13, 2005
    Date of Patent: October 27, 2009
    Assignee: Board of Regents University of Houston
    Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
  • Patent number: 7510819
    Abstract: A thin film solid oxide fuel cell (TFSOFC) having a porous metallic anode and a porous cathode is provided. The fuel cell is formed by using a continuous metal foil as a substrate onto which is deposited a thin anode metal layer which is then patterned to reveal an array of pores in the anode. A dense thin film electrolyte is then deposited onto the porous anode layer overcoating the anode and filling the anode pores. The substrate foil layer is then removed to allow for exposure of the porous anode/electrolyte to fuel. The cathode is then formed on the electrolyte by depositing a cathode thin film cap using known film deposition techniques. Further processing may be used to increase the porosity of the electrodes. The metal foil may be treated to have an atomically ordered surface, which makes possible an atomically ordered anode and atomically ordered thin film electrolyte for improved performance.
    Type: Grant
    Filed: May 18, 2006
    Date of Patent: March 31, 2009
    Assignee: Board of Regents, University of Houston
    Inventors: Xin Chen, Naijuan Wu, Alex Ignatiev, Yuxiang Zhou
  • Patent number: 7381492
    Abstract: A thin film solid oxide fuel cell (TFSOFC) having a porous metallic anode and a porous cathode is provided. The fuel cell is formed by using a continuous metal foil as a substrate to epitaxially deposit a thin film electrolyte on one surface of the foil. The metal foil may then be made porous by photolithographically patterning and etching the other surface of the foil to form holes extending through the foil to the electrolyte/foil interface. The cathode is then formed on the electrolyte by depositing a second thin film using known film deposition techniques. Further processing may be used to increase the porosity of the electrodes. The metal foil may be treated before film deposition to have an atomically ordered surface, which makes possible an atomically ordered thin film electrolyte.
    Type: Grant
    Filed: November 10, 2003
    Date of Patent: June 3, 2008
    Assignee: University of Houston
    Inventors: Xin Chen, Naijuan Wu, Alex Ignatiev
  • Publication number: 20060240575
    Abstract: The present invention provides a method for capturing optical micro detectors for improved surgical handling during implantation into an eye comprising the steps of providing an optically active thin film heterostructure on a soluble substrate; forming an array comprising individual optical microdetectors from the optically active thin film heterostructure; attaching the optical microdetector array onto a biodegradable polymer carrier membrane; and separating the optical microdetector array attached to the biodegradable polymer carrier membrane from the soluble substrate thereby capturing the optical microdetectors in the bio-polymer carrier membrane for improved handling of the optical micro-detectors during transfer and implantation into the eye.
    Type: Application
    Filed: June 27, 2006
    Publication date: October 26, 2006
    Inventors: NaiJuan Wu, Ali Zomorrodian, Alex Ignatiev
  • Publication number: 20060210706
    Abstract: A thin film solid oxide fuel cell (TFSOFC) having a porous metallic anode and a porous cathode is provided. The fuel cell is formed by using a continuous metal foil as a substrate onto which is deposited a thin anode metal layer which is then patterned to reveal an array of pores in the anode. A dense thin film electrolyte is then deposited onto the porous anode layer overcoating the anode and filling the anode pores. The substrate foil layer is then removed to allow for exposure of the porous anode/electrolyte to fuel. The cathode is then formed on the electrolyte by depositing a cathode thin film cap using known film deposition techniques. Further processing may be used to increase the porosity of the electrodes. The metal foil may be treated to have an atomically ordered surface, which makes possible an atomically ordered anode and atomically ordered thin film electrolyte for improved performance.
    Type: Application
    Filed: May 18, 2006
    Publication date: September 21, 2006
    Applicant: Board of Regents, University of Houston
    Inventors: Xin Chen, Naijuan Wu, Alex Ignatiev, Yuxiang Zhou
  • Publication number: 20050151156
    Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.
    Type: Application
    Filed: January 13, 2005
    Publication date: July 14, 2005
    Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
  • Publication number: 20050090874
    Abstract: The present invention provides a method for capturing optical micro detectors for improved surgical handling during implantation into an eye comprising the steps of providing an optically active thin film heterostructure on a soluble substrate; forming an array comprising individual optical microdetectors from the optically active thin film heterostructure; attaching the optical microdetector array onto a biodegradable polymer carrier membrane; and separating the optical microdetector array attached to the biodegradable polymer carrier membrane from the soluble substrate thereby capturing the optical microdetectors in the bio-polymer carrier membrane for improved handling of the optical micro-detectors during transfer and implantation into the eye.
    Type: Application
    Filed: June 15, 2002
    Publication date: April 28, 2005
    Inventors: Naijuan Wu, Ali Zomorrodian
  • Publication number: 20040157747
    Abstract: A thick atomically ordered single buffer layer for use in the integration of high temperature superconductor films with metallic substrates is disclosed. The buffer layer is a doped cerium oxide (CeO2) material, where the doping reduces layer cracking through the modification of thermal expansion coefficient and film strain properties, while adjusting chemical properties and lattice parameters to better match those of the substrate and HTS layer.
    Type: Application
    Filed: February 10, 2003
    Publication date: August 12, 2004
    Applicant: THE UNIVERSITY OF HOUSTON SYSTEM
    Inventors: Xin Chen, Naijuan Wu, Alex Ignatiev, Yimin Chen
  • Patent number: 6762481
    Abstract: A basic form of a variable capacitive apparatus and its actuating method are disclosed. The apparatus is a simple two-terminal structure and may be set by short duration, low voltage electrical pulses. Materials with perovskite structure or perovskite-related structures, especially colossal magnetoresistive materials, are the active constituents of the apparatus. The apparatus overcomes the shortcomings of its predecessors and offers the advantages of non-volatility, two or multi-level storage, non-destructive reading, free-of-power maintenance and potential high radiation hardness.
    Type: Grant
    Filed: October 8, 2002
    Date of Patent: July 13, 2004
    Assignee: The University of Houston System
    Inventors: Shangqing Liu, Naijuan Wu, Alex Ignatiev, JainRen Li
  • Publication number: 20040096572
    Abstract: A thin film solid oxide fuel cell (TFSOFC) having a porous metallic anode and a porous cathode is provided. The fuel cell is formed by using a continuous metal foil as a substrate to epitaxially deposit a thin film electrolyte on one surface of the foil. The metal foil may then be made porous by photolithographically patterning and etching the other surface of the foil to form holes extending through the foil to the electrolyte/foil interface. The cathode is then formed on the electrolyte by depositing a second thin film using known film deposition techniques. Further processing may be used to increase the porosity of the electrodes. The metal foil may be treated before film deposition to have an atomically ordered surface, which makes possible an atomically ordered thin film electrolyte.
    Type: Application
    Filed: November 10, 2003
    Publication date: May 20, 2004
    Applicant: UNIVERSITY OF HOUSTON
    Inventors: Xin Chen, Naijuan Wu, Alex Ignatiev