Patents by Inventor Raphael Tsu

Raphael Tsu 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: 5324965
    Abstract: A light emitting diode comprising microporous silicon of one conductivity type forming a PN junction with silicon of the opposite conductivity type and electrodes respectively connected to said regions, at least one of the electrodes being transparent.
    Type: Grant
    Filed: March 26, 1993
    Date of Patent: June 28, 1994
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Michael F. Tompsett, Raphael Tsu
  • Patent number: 5216262
    Abstract: A quantum well structure useful for semiconducting devices comprises two barrier regions and a thin epitaxially grown monocrystalline semiconductor material quantum well sandwiched between said barrier regions. Each barrier region consists essentially of alternate strain layers forming a superlattice, each of said layers being thinner than said quantum well. The layers are so thin that no defects are generated as a result of the release of stored strain energy.
    Type: Grant
    Filed: March 2, 1992
    Date of Patent: June 1, 1993
    Inventor: Raphael Tsu
  • Patent number: 5051786
    Abstract: The internal grain boundaries and intergranular spaces of polycrystalline semiconductor material may be passivated with an amorphous material, to substantially eliminate the dangling bonds at the internal grain boundaries. The passivated polycrystalline material of the present invention exhibits a lower electrically active defect density at the grain boundaries and intergranular space compared to unpassivated polycrystalline material. Moreover, large classes of amorphous passivating materials may be used for each known semiconductor material so that the passivating process may be readily adapted to existing process parameters and other device constraints. Passivated polycrystalline material may be employed to form the well or low energy bandgap layer of a quantum well device or superlattice, while still maintaining the required tunneling effect.
    Type: Grant
    Filed: October 24, 1989
    Date of Patent: September 24, 1991
    Assignee: MCNC
    Inventors: Edward H. Nicollian, Arnold Reiman, Raphael Tsu
  • Patent number: 4569697
    Abstract: Relatively dense, photovoltaic quality amorphous alloys which are characterized by reduced density of defect states in the band gaps thereof and which are particularly suited for use in tandem photovoltaic devices are formed by evaporating amorphous germanium and amorphous silicon in an ultrahigh vacuum environment, diffusing a density of states reducing element into and through the amorphous material, and finally annealing the resultant amorphous alloy to complete the diffusion process. The amorphous alloy, so formed, is a substantially contaminant-free, substantially tetrahedrally coordinated material. Fluorine is the preferred density of states reducing element which is added to the amorphous material for reducing the density of states through compensation, and for orbital promotion and expansion.
    Type: Grant
    Filed: August 26, 1983
    Date of Patent: February 11, 1986
    Assignee: Energy Conversion Devices, Inc.
    Inventors: Raphael Tsu, Stanford R. Ovshinsky, Jesus Hernandez, Denis Martin
  • Patent number: 4250515
    Abstract: A superlattice structure is disclosed in which alternating layers of semiductor alloy materials provide a one dimensional spatial periodic variation in band edge energy. A first layer of the superlattice device is an alloy including a first Group III material and a first Group V material, preferably In As, while the second layer is an alloy including a second Group III material different from the first Group III material and a second Group V material different from the first Group V material, and preferably GaSb. In the superlattice structure the valence band of the second alloy is closer to the conduction band of the first alloy than it is to the valence band of the first alloy.
    Type: Grant
    Filed: June 9, 1978
    Date of Patent: February 10, 1981
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Leo Esaki, Raphael Tsu, George A. Sai-Halasz, Leroy L. Chang
  • Patent number: 4163238
    Abstract: It is taught that infrared light can be produced by applying a voltage to a semiconductor device with a superlattice region and, further, that a population inversion can be achieved in such a device so that infrared amplification and oscillation can be produced. Methods of producing infrared radiation and of amplifying infrared radiation utilizing semiconductor devices with superlattice regions are disclosed. Also, semiconductor devices with superlattice regions for use as a laser amplifier or oscillator are taught.
    Type: Grant
    Filed: June 9, 1978
    Date of Patent: July 31, 1979
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Leo Esaki, Raphael Tsu