Patents by Inventor Xianhe LIU

Xianhe LIU 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: 20240128399
    Abstract: An epitaxial growth process, referred to as metal-semiconductor junction assisted epitaxy, of ultrawide bandgap aluminum gallium nitride (AlGaN) is disclosed. The epitaxy of AlGaN is performed in metal-rich (e.g., Ga-rich) conditions using plasma-assisted molecular beam epitaxy. The excess Ga layer leads to the formation of a metal-semiconductor junction during the epitaxy of magnesium (Mg)-doped AlGaN, which pins the Fermi level away from the valence band at the growth front. The Fermi level position is decoupled from Mg-dopant incorporation; that is, the surface band bending allows the formation of a nearly n-type growth front despite p-type dopant incorporation. With controlled tuning of the Fermi level by an in-situ metal-semiconductor junction during epitaxy, efficient p-type conduction can be achieved for large bandgap AlGaN.
    Type: Application
    Filed: December 13, 2023
    Publication date: April 18, 2024
    Inventors: Xianhe LIU, Ayush PANDEY, Zetian MI
  • Patent number: 11909176
    Abstract: An all-epitaxial, electrically injected surface-emitting green laser operates in a range of about 520-560 nanometers (nm). At 523 nm, for example, the device exhibits a threshold current density of approximately 0.4 kilo-amperes per square centimeter (kA/cm2), which is over one order of magnitude lower than that of previously reported blue laser diodes.
    Type: Grant
    Filed: October 15, 2020
    Date of Patent: February 20, 2024
    Assignee: The Regents of the University of Michigan
    Inventors: Yong-Ho Ra, Roksana Tonny Rashid, Xianhe Liu, Zetian Mi
  • Patent number: 11876147
    Abstract: An epitaxial growth process, referred to as metal-semiconductor junction assisted epitaxy, of ultrawide bandgap aluminum gallium nitride (AlGaN) is disclosed. The epitaxy of AlGaN is performed in metal-rich (e.g., Ga-rich) conditions using plasma-assisted molecular beam epitaxy. The excess Ga layer leads to the formation of a metal-semiconductor junction during the epitaxy of magnesium (Mg)-doped AlGaN, which pins the Fermi level away from the valence band at the growth front. The Fermi level position is decoupled from Mg-dopant incorporation; that is, the surface band bending allows the formation of a nearly n-type growth front despite p-type dopant incorporation. With controlled tuning of the Fermi level by an in-situ metal-semiconductor junction during epitaxy, efficient p-type conduction can be achieved for large bandgap AlGaN.
    Type: Grant
    Filed: May 28, 2019
    Date of Patent: January 16, 2024
    Assignee: THE REGENTS OF THE UNIVERSITY OF MICHIGAN
    Inventors: Xianhe Liu, Ayush Pandey, Zetian Mi
  • Publication number: 20230395746
    Abstract: A nanowire can include a first semiconductor portion, a second portion including a quantum structure disposed on the first portion, and a second semiconductor portion disposed on the second portion opposite the first portion. The quantum structure can include one or more quantum core structures and a quantum core shell disposed about the one or more quantum core structures. The one or more quantum core structures can include one or more quantum disks, quantum arch-shaped forms, quantum wells, quantum dots within quantum wells or combinations thereof.
    Type: Application
    Filed: August 17, 2023
    Publication date: December 7, 2023
    Inventors: Zetian MI, Yong-Ho RA, Roksana RASHID, Xianhe LIU
  • Patent number: 11804570
    Abstract: A nanowire can include a first semiconductor portion, a second portion including a quantum structure disposed on the first portion, and a second semiconductor portion disposed on the second portion opposite the first portion. The quantum structure can include one or more quantum core structures and a quantum core shell disposed about the one or more quantum core structures. The one or more quantum core structures can include one or more quantum disks, quantum arch-shaped forms, quantum wells, quantum dots within quantum wells or combinations thereof.
    Type: Grant
    Filed: July 24, 2018
    Date of Patent: October 31, 2023
    Assignee: THE REGENTS OF THE UNIVERSITY OF MICHIGAN
    Inventors: Zetian Mi, Yong-Ho Ra, Roksana Rashid, Xianhe Liu
  • Publication number: 20230079101
    Abstract: Nanowire light emitting diodes (LEDs) are operable for spontaneous emission of light at significantly reduced current densities and with very narrow linewidths relative to conventional LEDs.
    Type: Application
    Filed: February 18, 2021
    Publication date: March 16, 2023
    Inventors: Xianhe LIU, Yuanpeng WU, Yakshita MALHOTRA, Yi SUN, Seth COE-SULLIVAN, Matthew STEVENSON, Zetian MI
  • Publication number: 20220367561
    Abstract: In various embodiments, the present disclosure includes a nitrogen-polar (N-polar) nanowire that includes an indium gallium nitride (InGaN) quantum well formed by selective area growth. It is noted that the N-polar nanowire is operable for emitting light.
    Type: Application
    Filed: May 16, 2022
    Publication date: November 17, 2022
    Inventors: Xianhe LIU, Yi SUN, Yakshita MALHOTRA, Ayush PANDEY, Ping WANG, Yuanpeng WU, Kai SUN, Zetian MI
  • Publication number: 20210119420
    Abstract: An all-epitaxial, electrically injected surface-emitting green laser operates in a range of about 520-560 nanometers (nm). At 523 nm, for example, the device exhibits a threshold current density of approximately 0.4 kilo-amperes per square centimeter (kA/cm2), which is over one order of magnitude lower than that of previously reported blue laser diodes.
    Type: Application
    Filed: October 15, 2020
    Publication date: April 22, 2021
    Inventors: Yong-Ho RA, Roksana Tonny RASHID, Xianhe LIU, Zetian MI
  • Publication number: 20190363218
    Abstract: An epitaxial growth process, referred to as metal-semiconductor junction assisted epitaxy, of ultrawide bandgap aluminum gallium nitride (AlGaN) is disclosed. The epitaxy of AlGaN is performed in metal-rich (e.g., Ga-rich) conditions using plasma-assisted molecular beam epitaxy. The excess Ga layer leads to the formation of a metal-semiconductor junction during the epitaxy of magnesium (Mg)-doped AlGaN, which pins the Fermi level away from the valence band at the growth front. The Fermi level position is decoupled from Mg-dopant incorporation; that is, the surface band bending allows the formation of a nearly n-type growth front despite p-type dopant incorporation. With controlled tuning of the Fermi level by an in-situ metal-semiconductor junction during epitaxy, efficient p-type conduction can be achieved for large bandgap AlGaN.
    Type: Application
    Filed: May 28, 2019
    Publication date: November 28, 2019
    Inventors: Xianhe LIU, Ayush PANDEY, Zetian MI
  • Publication number: 20190148583
    Abstract: A nanowire can include a first semiconductor portion, a second portion including a quantum structure disposed on the first portion, and a second semiconductor portion disposed on the second portion opposite the first portion. The quantum structure can include one or more quantum core structures and a quantum core shell disposed about the one or more quantum core structures. The one or more quantum core structures can include one or more quantum disks, quantum arch-shaped forms, quantum wells, quantum dots within quantum wells or combinations thereof.
    Type: Application
    Filed: July 24, 2018
    Publication date: May 16, 2019
    Inventors: Zetian MI, Yong-Ho RA, Roksana RASHID, Xianhe LIU