USA As Represented by Secretary of the Navy

Boris N Feigelson

Alan G Jacobs

James A Wollmershauser

Francis J Kub

Travis J Anderson

Marko J Tadjer

Benjamin L Greenberg

James C Gallagher

Kedar Manandhar

Michael Shur

Jordan D Greenlee

Charles R Eddy, Jr

Edward P Gorzkowski, Iii

Eugene A Imhoff

Robert E Stahlbush

Jennifer K Hite

Alexander L Efros

Nadeemullah A Mahadik

John Drazin

Dana A Kazerooni

Kevin P Anderson

Richard L Henry

RF susceptors manufactured by means of 3D printing. 3D-printed susceptors in accordance with the invention include susceptors having solid or mesh walls, where the susceptors are in the form of hollow cylinders, pyramids, spheres, hemispheres, ellipsoids, paraboloids, toroids, or prisms; flat planes; or other hollow or solid three-dimensional shapes. The 3D-printed susceptors can be formed from any suitable starting material, such as tungsten powder, graphite, silicon carbide, molybdenum powder, tantalum powder, rhenium powder, or alloys thereof, or can be formed such that some portions of the susceptors are formed from one or more materials while other portions are formed from different material(s).

3D printed susceptor for rapid indirect RF heating

A bipolar nanocomposite semiconductor (BNS) material in which electrons and holes are separately transported throughout the BNS volume via an interpenetrating plurality of networks, where some of the networks have one conductivity type and others have the opposite conductivity type. The interpenetrating networks can include one or more multiple nanocrystalline structures, metal and dielectric networks and are intimately connected to enable band-like transport of both electrons and holes throughout the material.

Bipolar nanocomposite semiconductors

Methods for efficient doping of wide-bandgap (WBG) and ultrawide-bandgap (UWBG) semiconductors by implantation, and WBG and UWBG semiconductors made using the disclosed methods. A p-type semiconductor region is formed by implanting specified acceptor and donor co-dopant atoms in a predetermined ratio, e.g., two acceptors to one donor (ADA), into the semiconductor lattice. An n-type type semiconductor region is by implanting specified donor and acceptor co-dopant atoms in a predetermined ratio, e.g., two donors to one acceptor (DAD), into the semiconductor lattice. Compensator atoms are also implanted into the lattice to complete formula units in the crystal lattice structure and preserve the stoichiometry of the semiconductor material. The doped material is then annealed to activate the dopants and repair any damage to the lattice that might have occurred during implantation.

WBG and UWBG semiconductor with p- and n-type conductivity and process for making the same

Thermoelectric (TE) nanocomposite material that includes at least one component consisting of nanocrystals. A TE nanocomposite material in accordance with the present invention can include, but is not limited to, multiple nanocrystalline structures, nanocrystal networks or partial networks, or multi-component materials, with some components forming connected interpenetrating networks including nanocrystalline networks. The TE nanocomposite material can be in the form of a bulk solid having semiconductor nanocrystallites that form an electrically conductive network within the material. In other embodiments, the TE nanocomposite material can be a nanocomposite thermoelectric material having one network of p-type or n-type semiconductor domains and a low thermal conductivity semiconductor or dielectric network or domains separating the p-type or n-type domains that provides efficient phonon scattering to reduce thermal conductivity while maintaining the electrical properties of the p-type or n-type semiconductor.

Thermoelectric nanocomposite materials

A method for activating implanted dopants and repairing damage to dopant-implanted GaN to form n-type or p-type GaN. A GaN substrate is implanted with n- or p-type ions and is subjected to a high-temperature anneal to activate the implanted dopants and to produce planar n- or p-type doped areas within the GaN having an activated dopant concentration of about 10-10cm. An initial annealing at a temperature at which the GaN is stable at a predetermined process temperature for a predetermined time can be conducted before the high-temperature anneal. A thermally stable cap can be applied to the GaN substrate to suppress nitrogen evolution from the GaN surface during the high-temperature annealing step. The high-temperature annealing can be conducted under Npressure to increase the stability of the GaN. The annealing can be conducted using laser annealing or rapid thermal annealing (RTA).

GaN devices with ion implanted ohmic contacts and method of fabricating devices incorporating the same

A thermionic dispenser cathode having a refractory metal matrix with scandium and barium compounds in contact with the metal matrix and methods for forming the same. The invention utilizes atomic layer deposition (ALD) to form a nanoscale, uniform, conformal distribution of a scandium compound on tungsten surfaces and further utilizes in situ high pressure consolidation/impregnation to enhance impregnation of a BaO&#x2014;CaO&#x2014;AlObased emissive mixture into the scandate-coated tungsten matrix or to sinter a tungsten/scandate/barium composite structure. The result is a tungsten-scandate thermionic cathode having improved emission.

Thermionic tungsten/scandate cathodes and method of making the same

An enhanced symmetric multicycle rapid thermal annealing process for removing defects and activating implanted dopant impurities in a III-nitride semiconductor sample. A sample is placed in an enclosure and heated to a temperature Tunder an applied pressure Pfor a time t. While the heating of the sample is maintained, the sample is subjected to a series of rapid laser irradiations under an applied pressure Pand a baseline temperature T. Each of the laser irradiations heats the sample to a temperature Tabove its thermodynamic stability limit. After a predetermined number of temperature pulses or a predetermined period of time, the laser irradiations are stopped and the sample is brought to a temperature Tand held at Tfor a time tto complete the annealing.

Implanted dopant activation for wide bandgap semiconductor electronics

A new Enhanced High Pressure Sintering (EHPS) method for making three-dimensional fully dense nanostructures and nano-heterostructures formed from nanoparticle powders, and three-dimensional fully dense nanostructures and nano-heterostructures formed using that method. A nanoparticle powder is placed into a reaction chamber and is treated at an elevated temperature under a gas flow to produce a cleaned powder. The cleaned powder is formed into a low density green compact which is then sintered at a temperature below conventional sintering temperatures to produce a fully dense bulk material having a retained nanostructure or nano-heterostructure corresponding to the nanostructure of the constituent nanoparticles. All steps are performed without exposing the nanoparticle powder to the ambient.

Bulk monolithic nano-heterostructures and method of making the same

A process for producing metastable nanocrystalline alpha-alumina (&#x3b1;-AlO) having particle sizes smaller than 12 nm. Starting crystallites of &#x3b1;-AlOhaving a particle size larger than 12 nm, typically on the order of about 50 nm, are ball-milled at low temperatures to produce a nanocrystalline &#x3b1;-AlOpowder having a particle size of less than 12 nm, i.e., below the theoretical room temperature thermodynamic size limit at which &#x3b1;-AlOchanges phase to &#x3b3;-AlO, wherein the powder remains in the &#x3b1;-AlOphase at all times.

Nanocrystalline alpha alumina and method for making the same

A method for making transparent nanocomposite ceramics and other solid bulk materials from nanoparticle powders and transparent nanocomposite ceramics and other solid bulk materials formed using that method. A nanoparticle powder is placed into a reaction chamber and is treated to produce a clean surface powder. The clean surface powder is coated with a second material by means of p-ALD to produce core/shell or core multi shell nanoparticles having a coating or coatings of a other material surrounding the nanoparticle. The core/shell nanoparticles are cleaned and formed into green compact which is sintered to produce a transparent nanocomposite ceramic or other solid bulk material consisting of nanoparticles or core/shell nanoparticles uniformly embedded in a matrix of a different material, particularly in a matrix of a different ceramic material, formed by outer shell of initial core/shell. All steps are performed without exposing the material to the ambient.

Growing community of inventors

Springfield, VA, United States of America

Boris N Feigelson