Patents by Inventor Zhizhang Chen

Zhizhang Chen 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).

  • Publication number: 20030143788
    Abstract: An emitter includes an electron supply and a tunneling layer disposed on the electron supply. A cathode layer is disposed on the tunneling layer. A conductive electrode has multiple layers of conductive material. The multiple layers include a protective layer disposed on the cathode layer. The conductive electrode has been etched to define an opening thereby exposing a portion of the cathode layer.
    Type: Application
    Filed: January 31, 2002
    Publication date: July 31, 2003
    Inventors: Zhizhang Chen, Paul J. Benning, Sriram Ramamoorthi, Thomas Novet
  • Publication number: 20030089900
    Abstract: An emitter has an electron supply and a porous cathode layer having nanohole openings. The emitter also has a tunneling layer disposed between the electron supply and the cathode layer.
    Type: Application
    Filed: October 1, 2002
    Publication date: May 15, 2003
    Inventors: Zhizhang Chen, Sriram Ramamoorthi, Hung Liao, Paul Benning, Alexander Govyadinov
  • Patent number: 6558968
    Abstract: An emitter has an electron supply layer and a tunneling layer formed on the electron supply layer. Optionally, an insulator layer is formed on the electron supply layer and has openings defined within in which the tunneling layer is formed. A cathode layer is formed on the tunneling layer. A conductive layer is partially disposed on the cathode layer and partially on the insulator layer if present. The conductive layer defines an opening to provide a surface for energy emissions of electrons and/or photons. Preferably but optionally, the emitter is subjected to an annealing process thereby increasing the supply of electrons tunneled from the electron supply layer to the cathode layer.
    Type: Grant
    Filed: October 31, 2001
    Date of Patent: May 6, 2003
    Assignee: Hewlett-Packard Development Company
    Inventors: Sriram Ramamoorthi, Zhizhang Chen
  • Publication number: 20030080330
    Abstract: An emitter has an electron supply layer and a tunneling layer formed on the electron supply layer. Optionally, an insulator layer is formed on the electron supply layer and has openings defined within in which the tunneling layer is formed. A cathode layer is formed on the tunneling layer. A conductive layer is partially disposed on the cathode layer and partially on the insulator layer if present. The conductive layer defines an opening to provide a surface for energy emissions of electrons and/or photons. Preferably but optionally, the emitter is subjected to an annealing process thereby increasing the supply of electrons tunneled from the electron supply layer to the cathode layer.
    Type: Application
    Filed: October 31, 2001
    Publication date: May 1, 2003
    Inventors: Sriram Ramamoorthi, Zhizhang Chen
  • Publication number: 20020190623
    Abstract: A method for creating an electron lens includes the steps of applying a polymer layer on an emitter surface of an electron emitter and then curing the polymer layer to reduce volatile content.
    Type: Application
    Filed: June 14, 2001
    Publication date: December 19, 2002
    Inventors: Zhizhang Chen, Ronald L. Enck, Sriram Ramamoorthi, Qin Liu
  • Publication number: 20020167001
    Abstract: An emitter has an electron supply layer and a tunneling layer formed on the electron supply layer. Optionally, an insulator layer is formed on the electron supply layer and has openings defined within in which the tunneling layer is formed. A cathode layer is formed on the tunneling layer to provide a surface for energy emissions of electrons and/or photons. Preferably, the emitter is subjected to an annealing process thereby increasing the supply of electrons tunneled from the electron supply layer to the cathode layer.
    Type: Application
    Filed: April 30, 2001
    Publication date: November 14, 2002
    Inventors: Zhizhang Chen, Michael J. Regan, Brian E. Bolf, Thomas Novet, Paul J. Benning, Mark Alan Johnstone, Sriram Ramamoorthi
  • Patent number: 5766964
    Abstract: Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime .tau. and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime .tau. and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step.
    Type: Grant
    Filed: December 22, 1995
    Date of Patent: June 16, 1998
    Assignee: Georgia Tech Research Corporation
    Inventors: Ajeet Rohatgi, Parag Doshi, John Keith Tate, Jose Mejia, Zhizhang Chen
  • Patent number: 5510271
    Abstract: Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime .tau. and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. Silicon solar cell efficiencies of 16.9% have been achieved. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime .tau. and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step.
    Type: Grant
    Filed: September 9, 1994
    Date of Patent: April 23, 1996
    Assignee: Georgia Tech Research Corporation
    Inventors: Ajeet Rohatgi, Zhizhang Chen, Parag Doshi
  • Patent number: 5462898
    Abstract: A new process has been developed to achieve a very low SiO.sub.x /Si interface state density D.sub.it, low recombination velocity S (<2 cm/s), and high effective carrier lifetime T.sub.eff (>5 ms) for oxides deposited on silicon substrates at low temperature. The technique involves direct plasma-enhanced chemical vapor deposition (PECVD), with appropriate growth conditions, followed by a photo-assisted rapid thermal annealing (RTA) process. Approximately 500-A-thick SiO.sub.x layers are deposited on Si by PECVD at 250.degree. C. with 0.02 W/cm.sup.-2 rf power, then covered with SiN or an evaporated thin aluminum layer, and subjected to a photo-assisted anneal in forming gas ambient at 350.degree. C., resulting in an interface state density D.sub.it in the range of about 1-4.times.10.sup.10 cm.sup.-2 eV.sup.-1, which sets a record for the lowest interface state density D.sub.it for PECVD oxides fabricated to date.
    Type: Grant
    Filed: May 25, 1994
    Date of Patent: October 31, 1995
    Assignee: Georgia Tech Research Corporation
    Inventors: Zhizhang Chen, Ajeet Rohatgi
  • Patent number: 5418019
    Abstract: A sequential plasma-enhanced chemical vapor deposition (PECVD) of SiN and SiO.sub.x produces a very effective double-layer antireflection coating. This antireflection coating is compared with the frequently used and highly efficient double-layer MgF.sub.2 /ZnS coating. It is shown that the double-layer SiO.sub.x /SiN coating improves the short-circuited current (J.sub.sc) by 47%, open-circuit voltage (V.sub.oc) by 3.7%, and efficiency (Eff) by 55% for silicon cells with oxide surface passivation. The counterpart MgF.sub.2 /ZnS coating gives smaller improvement in V.sub.oc and Eff. However, if silicon cells do not have the oxide passivation, the PECVD SiO.sub.x /SiN gives much greater improvement in the cell parameters, 57% in J.sub.sc, 8% in V.sub.oc, and 66% in efficiency, compared to the MgF.sub.2 /ZnS coating which improves J.sub.sc by 50%, V.sub.oc by 2%, and cell efficiency by 54%. This significant additional improvement results from the PECVD deposition-induced surface/defect passivation.
    Type: Grant
    Filed: May 25, 1994
    Date of Patent: May 23, 1995
    Assignee: Georgia Tech Research Corporation
    Inventors: Zhizhang Chen, Ajeet Rohatgi