Patents by Inventor Mahendra Kumar Sunkara
Mahendra Kumar Sunkara 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: 20230286826Abstract: A method of manufacturing a mixed metal oxide powder is provided. The method includes steps of mixing two or more metal precursors in a solvent to form a dispersion of the metal precursors in the solvent; drying the dispersion to obtain a dried mixed metal precursor powder; jet milling the dried mixed metal precursor powder to obtain particles having a size distribution in a range of 0.2-20 micrometers; and exposing the particles to a hydrocarbon flame or oxygen plasma to provide the mixed metal oxide powder. Mixed metal oxide powders produced by the disclosed methods are also provided.Type: ApplicationFiled: March 13, 2023Publication date: September 14, 2023Inventors: Mahendra Kumar Sunkara, Vivekanand Kumar, Tu Q. Nguyen
-
Patent number: 11183682Abstract: The present development is a process for the preparation of nanowire synthesis, coatings and uses thereof. Lithium titanate (LTO) nanowires are synthesized using a continuous hydrocarbon/plasma flame process technology combined with the dry impregnation method. The resulting LTO nanowires can be used as electro active anode materials for lithium ion batteries. The coating parameters, such as thickness, porosity of the film, packing density, and viscosity are controlled using the length of the nanowires, calendaring pressure, and slurry composition.Type: GrantFiled: August 29, 2019Date of Patent: November 23, 2021Assignee: Advanced Energy Materials, LLCInventors: Mahendra Kumar Sunkara, Vivekanand Kumar, Veerendra Atla
-
Publication number: 20200075932Abstract: The present development is a process for the preparation of nanowire synthesis, coatings and uses thereof. Lithium titanate (LTO) nanowires are synthesized using a continuous hydrocarbon/plasma flame process technology combined with the dry impregnation method. The resulting LTO nanowires can be used as electro active anode materials for lithium ion batteries. The coating parameters, such as thickness, porosity of the film, packing density, and viscosity are controlled using the length of the nanowires, calendaring pressure, and slurry composition.Type: ApplicationFiled: August 29, 2019Publication date: March 5, 2020Inventors: Mahendra Kumar Sunkara, Vivekanand Kumar, Veerendra Atla
-
Patent number: 9755023Abstract: The composition of matter comprising Ga(Sbx)N1?x where x=0.01 to 0.06 is characterized by a band gap between 2.4 and 1.7 eV. A semiconductor device includes a semiconductor layer of that composition. A photoelectric cell includes that semiconductor device.Type: GrantFiled: September 28, 2012Date of Patent: September 5, 2017Assignees: The University of Kentucky Research Foundation, The University of Louisville Research Foundation, Inc.Inventors: Madhu Menon, Michael Sheetz, Mahendra Kumar Sunkara, Chandrashekhar Pendyala, Swathi Sunkara, Jacek B. Jasinski
-
Patent number: 9630162Abstract: A reactor and method for production of nanostructures, including metal oxide nanowires or nanoparticles, are provided. The reactor includes a regulated metal powder delivery system in communication with a dielectric tube; a plasma-forming gas inlet, whereby a plasma-forming gas is delivered substantially longitudinally into the dielectric tube; a sheath gas inlet, whereby a sheath gas is delivered into the dielectric tube; and a microwave energy generator coupled to the dielectric tube, whereby microwave energy is delivered into a plasma-forming gas. The method for producing nanostructures includes providing a reactor to form nanostructures and collecting the formed nanostructures, optionally from a filter located downstream of the dielectric tube.Type: GrantFiled: April 4, 2012Date of Patent: April 25, 2017Assignee: University of Louisville Research Foundation, Inc.Inventors: Mahendra Kumar Sunkara, Jeong H. Kim, Vivekanand Kumar
-
Patent number: 9409141Abstract: A method of synthesizing a metal oxide nanowire includes the steps of: combining an amount of a transition metal or a transition metal oxide with an amount of an alkali metal compound to produce a mixture; activating a plasma discharge reactor to create a plasma discharge; exposing the mixture to the plasma discharge for a first predetermined time period such that transition metal oxide nanowires are formed; contacting the transition metal oxide nanowires with an acid solution such that an alkali metal ion is exchanged for a hydrogen ion on each of the transition metal oxide nanowires; and exposing the transition metal oxide nanowires to the plasma discharge for a second predetermined time period to thermally anneal the transition metal oxide nanowires. Transition metal oxide nanowires produced using the synthesis methods described herein are also provided.Type: GrantFiled: July 14, 2011Date of Patent: August 9, 2016Assignee: University of Louisville Research FoundationInventors: Mahendra Kumar Sunkara, Vivekanand Kumar, Jeong H. Kim, Ezra Lee Clark
-
Patent number: 8920970Abstract: An anode material for lithium-ion batteries is provided that comprises an elongated core structure capable of forming an alloy with lithium; and a plurality of nanostructures placed on a surface of the core structure, with each nanostructure being capable of forming an alloy with lithium and spaced at a predetermined distance from adjacent nanostructures.Type: GrantFiled: December 30, 2009Date of Patent: December 30, 2014Assignee: University of Louisville Research FoundationInventors: Mahendra Kumar Sunkara, Praveen Meduri, Gamini Sumanasekera
-
Publication number: 20130017145Abstract: A method of synthesizing a metal oxide nanowire includes the steps of: combining an amount of a transition metal or a transition metal oxide with an amount of an alkali metal compound to produce a mixture; activating a plasma discharge reactor to create a plasma discharge; exposing the mixture to the plasma discharge for a first predetermined time period such that transition metal oxide nanowires are formed; contacting the transition metal oxide nanowires with an acid solution such that an alkali metal ion is exchanged for a hydrogen ion on each of the transition metal oxide nanowires; and exposing the transition metal oxide nanowires to the plasma discharge for a second predetermined time period to thermally anneal the transition metal oxide nanowires. Transition metal oxide nanowires produced using the synthesis methods described herein are also provided.Type: ApplicationFiled: July 14, 2011Publication date: January 17, 2013Inventors: Mahendra Kumar Sunkara, Vivekanand Kumar, Jeong H. Kim, Ezra Lee Clark
-
Publication number: 20120028124Abstract: An anode material for lithium-ion batteries is provided that comprises an elongated core structure capable of forming an alloy with lithium; and a plurality of nanostructures placed on a surface of the core structure, with each nanostructure being capable of forming an alloy with lithium and spaced at a predetermined distance from adjacent nanostructures.Type: ApplicationFiled: December 30, 2009Publication date: February 2, 2012Applicant: UNIVERSITY OF LOUISVILLE RESEARCH FOUNDATION, INC.Inventors: Mahendra Kumar Sunkara, Praveen Meduri, Gamini Sumanasekera
-
Publication number: 20120027955Abstract: A reactor and method for production of nanostructures produces, for example, metal oxide nanowires or nanoparticles. The reactor includes a metal powder delivery system wherein the metal powder delivery system includes a funnel in communication with a dielectric tube; a plasma-forming gas inlet, whereby a plasma-forming gas is delivered substantially longitudinally into the dielectric tube; a sheath gas inlet, whereby a sheath gas is delivered into the dielectric tube; and a microwave energy generator coupled to the dielectric tube, whereby microwave energy is delivered into a plasma-forming gas. The method for producing nanostructures includes delivering a plasma-forming gas substantially longitudinally into a dielectric tube; delivering a sheath gas into the tube; forming a plasma from the plasma-forming gas by applying microwave energy to the plasma-forming gas; delivering a metal powder into the dielectric tube; and reacting the metal powder within the plasma to form metal oxide nanostructures.Type: ApplicationFiled: October 9, 2008Publication date: February 2, 2012Inventors: Mahendra Kumar Sunkara, Jeong H. Kim, Vivekanand Kumar
-
Patent number: 7819974Abstract: A synthesis route to grow textured thin film of gallium nitride on amorphous quartz substrates and on single crystalline substrates such as c-sapphire and polycrystalline substrates such as pyrolytic boron nitride (PBN), alumina and quartz using the dissolution of atomic nitrogen rather than molecular nitrogen to allow for growth at subatmospheric pressure.Type: GrantFiled: July 3, 2007Date of Patent: October 26, 2010Assignee: University of Louisville Research Foundation, Inc.Inventors: Mahendra Kumar Sunkara, Hari Chandrasekaran, Hongwei Li
-
Patent number: 7771689Abstract: A process of synthesizing metal and metal nitride nanowires, the steps comprising of: forming a catalytic metal (such as gallium, and indium) on a substrate (such as fused silica quartz, pyrolytic boron nitride, alumina, and sapphire), heating the combination in a pressure chamber, adding gaseous reactant and/or solid metal source, applying sufficient microwave energy (or current in hot filament reactor) to activate the metal of interest (such as gold, copper, tungsten, and bismuth) and continuing the process until nanowires of the desired length are formed. The substrate may be fused silica quartz, the catalytic metal a gallium or indium metal, the gaseous reactant is nitrogen and/or hydrogen and the nanowires are tungsten nitride and/or tungsten.Type: GrantFiled: November 10, 2003Date of Patent: August 10, 2010Assignee: University of Louisville Research Foundation, IncInventors: Mahendra Kumar Sunkara, Hari Chandrasekaran, Hongwei Li
-
Patent number: 7713352Abstract: A process is provided to produce bulk quantities of nanowires in a variety of semiconductor materials. Thin films and droplets of low-melting metals such as gallium, indium, bismuth, and aluminum are used to dissolve and to produce nanowires. The dissolution of solutes can be achieved by using a solid source of solute and low-melting metal, or using a vapor phase source of solute and low-melting metal. The resulting nanowires range in size from 1 nanometer up to 1 micron in diameter and lengths ranging from 1 nanometer to several hundred nanometers or microns. This process does not require the use of metals such as gold and iron in the form of clusters whose size determines the resulting nanowire size. In addition, the process allows for a lower growth temperature, better control over size and size distribution, and better control over the composition and purity of the nanowire produced therefrom.Type: GrantFiled: September 14, 2006Date of Patent: May 11, 2010Assignee: University of Louisville Research Foundation, Inc.Inventors: Mahendra Kumar Sunkara, Shashank Sharma, Hari Chandrasekaran, Hongwei Li, Sreeram Vaddiraju
-
Patent number: 7597941Abstract: A method of synthesizing and controlling the internal diameters, conical angles, and morphology of tubular carbon nano/micro structures. Different morphologies can be synthesized included but not limited to cones, straight tubes, nozzles, cone-on-tube (funnels), tube-on-cone, cone-tube-cone, n-staged structures, multijunctioned tubes, Y-junctions, dumbbell (pinched morphology) and capsules. The process is based on changing the wetting behavior of a low melting metals such as gallium, indium, and aluminum with carbon using a growth environment of different gas phase chemistries. The described carbon tubular morphologies can be synthesized using any kind of gas phase excitation such as, but not limited to, microwave excitation, hot filament excitation, thermal excitation and Radio Frequency (RF) excitations. The depositions area is only limited by the substrate area in the equipment used and not limited by the process.Type: GrantFiled: September 9, 2004Date of Patent: October 6, 2009Assignee: University of Louisville Research Foundation, Inc.Inventors: Mahendra Kumar Sunkara, Gopinath Bhimarasetti
-
Patent number: 7591897Abstract: A process for the rapid synthesis of metal oxide nanoparticles at low temperatures and methods which facilitate the fabrication of long metal oxide nanowires. The method is based on treatment of metals with oxygen plasma. Using oxygen plasma at low temperatures allows for rapid growth unlike other synthesis methods where nanomaterials take a long time to grow. Density of neutral oxygen atoms in plasma is a controlling factor for the yield of nanowires. The oxygen atom density window differs for different materials. By selecting the optimal oxygen atom density for various materials the yield can be maximized for nanowire synthesis of the metal.Type: GrantFiled: March 20, 2006Date of Patent: September 22, 2009Assignee: University of Louisville Research Foundation, Inc.Inventors: Mahendra Kumar Sunkara, Sreeram Vaddiraju, Miran Mozetic, Uros Cvelbar
-
Patent number: 7445671Abstract: A method of producing networks of low melting metal oxides such as crystalline gallium oxide comprised of one-dimensional nanostructures. Because of the unique arrangement of wires, these crystalline networks defined as “nanowebs”, “nanowire networks”, and/or “two-dimensional nanowires”. Nanowebs contain wire densities on the order of 109/cm2. A possible mechanism for the fast self-assembly of crystalline metal oxide nanowires involves multiple nucleation and coalescence via oxidation-reduction reactions at the molecular level. The preferential growth of nanowires parallel to the substrate enables them to coalesce into regular polygonal networks. The individual segments of the polygonal network consist of both nanowires and nanotubules of ?-gallium oxide. The synthesis of highly crystalline noncatalytic low melting metals such as ?-gallium oxide tubes, nanowires, and nanopaintbrushes is accomplished using molten gallium and microwave plasma containing a mixture of monoatomic oxygen and hydrogen.Type: GrantFiled: June 16, 2004Date of Patent: November 4, 2008Assignees: University of Louisville, University of KentuckyInventors: Mahendra Kumar Sunkara, Shashank Sharma, Burtron H. Davis, Uschi M. Graham
-
Publication number: 20080194085Abstract: A synthesis route to grow textured thin film of gallium nitride on amorphous quartz substrates and on single crystalline substrates such as c-sapphire and polycrystalline substrates such as pyrolytic boron nitride (PBN), alumina and quartz using the dissolution of atomic nitrogen rather than molecular nitrogen to allow for growth at subatmospheric pressure.Type: ApplicationFiled: July 3, 2007Publication date: August 14, 2008Inventors: Mahendra Kumar Sunkara, Hari Chandrasekaran, Hongwei Li
-
Patent number: 7241432Abstract: This invention presents a process to produce bulk quantities of nanowires of a variety of semiconductor materials. Large liquid gallium drops are used as sinks for the gas phase solute, generated in-situ facilitated by microwave plasma. To grow silicon nanowires for example, a silicon substrate covered with gallium droplets is exposed to a microwave plasma containing atomic hydrogen. A range of process parameters such as microwave power, pressure, inlet gas phase composition, were used to synthesize silicon nanowires as small as 4 nm (nanometers) in diameter and several micrometers long. As opposed to the present technology, the instant technique does not require creation of quantum sized liquid metal droplets to synthesize nanowires. In addition, it offers advantages such as lower growth temperature, better control over size and size distribution, better control over the composition and purity of the nanowires.Type: GrantFiled: September 1, 2006Date of Patent: July 10, 2007Assignee: University of LouisvilleInventors: Shashank Sharma, Mahendra Kumar Sunkara
-
Patent number: 7238232Abstract: A synthesis route to grow textured thin film of gallium nitride on amorphous quartz substrates and on single crystalline substrates such as c-sapphire and polycrystalline substrates such as pyrolytic boron nitride (PBN), alumina and quartz using the dissolution of atomic nitrogen rather than molecular nitrogen to allow for growth at subatmospheric pressure.Type: GrantFiled: April 30, 2003Date of Patent: July 3, 2007Assignee: University of LouisvilleInventors: Mahendra Kumar Sunkara, Hari Chandrasekaran, Hongwei Li
-
Patent number: 7182812Abstract: The bulk synthesis of highly crystalline noncatalytic low melting metals such as ?-gallium oxide tubes, nanowires, and nanopaintbrushes is accomplished using molten gallium and microwave plasma containing a mixture of monoatomic oxygen and hydrogen. Gallium oxide nanowires were 20–100 nm thick and tens to hundreds of microns long. Transmission electron microscopy (TEM) revealed the nanowires to be highly crystalline and devoid of any structural defects. Results showed that multiple nucleation and growth of gallium oxide nanostructures can occur directly out of molten gallium exposed to appropriate composition of hydrogen and oxygen in the gas phase. These gallium oxide nanostructures are of particular interest for opto-electronic devices and catalytic applications.Type: GrantFiled: September 16, 2003Date of Patent: February 27, 2007Assignee: University of LouisvilleInventors: Mahendra Kumar Sunkara, Shashank Sharma