Patents by Inventor L. Ralph Dawson

L. Ralph Dawson 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: 5625635
    Abstract: An infrared emitting device and method. The infrared emitting device comprises a III-V compound semiconductor substrate upon which are grown a quantum-well active region having a plurality of quantum-well layers formed of a ternary alloy comprising InAsSb sandwiched between barrier layers formed of a ternary alloy having a smaller lattice constant and a larger energy bandgap than the quantum-well layers. The quantum-well layers are preferably compressively strained to increase the threshold energy for Auger recombination; and a method is provided for determining the preferred thickness for the quantum-well layers. Embodiments of the present invention are described having at least one cladding layer to increase the optical and carrier confinement in the active region, and to provide for waveguiding of the light generated within the active region.
    Type: Grant
    Filed: November 28, 1994
    Date of Patent: April 29, 1997
    Assignee: Sandia Corporation
    Inventors: Steven R. Kurtz, Robert M. Biefeld, L. Ralph Dawson, Arnold J. Howard, Kevin C. Baucom
  • Patent number: 5065205
    Abstract: A high gain photoconductive device for 8 to 12 .mu.m wavelength radiation including an active semiconductor region extending from a substrate to an exposed face, the region comprising a strained-layer superlattice of alternating layers of two different InAs.sub.1-x Sb.sub.x compounds having x>0.75. A pair of spaced electrodes are provided on the exposed face, and changes in 8 to 12 .mu.m radiation on the exposed face cause a large photoconductive gain between the spaced electrodes.
    Type: Grant
    Filed: May 12, 1989
    Date of Patent: November 12, 1991
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Robert M. Biefeld, L. Ralph Dawson, Ian J. Fritz, Steven R. Kurtz, Thomas E. Zipperian
  • Patent number: 5055890
    Abstract: A layered semiconductor device with a nonvolatile three dimensional memory comprises a storage channel which stores charge carriers. Charge carriers flow laterally through the storage channel from a source to a drain. Isolation material, either a Schottky barrier or a heterojunction, located in a trench of an upper layer controllably retains the charge within the a storage portion determined by the confining means. The charge is retained for a time determined by the isolation materials' nonvolatile characteristics or until a change of voltage on the isolation material and the source and drain permit a read operation. Flow of charge through an underlying sense channel is affected by the presence of charge within the storage channel, thus the presences of charge in the memory can be easily detected.
    Type: Grant
    Filed: January 25, 1990
    Date of Patent: October 8, 1991
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: L. Ralph Dawson, Gordon C. Osbourn, Paul S. Peercy, Harry T. Weaver, Thomas E. Zipperian