Patents by Inventor Ashok K. Sood

Ashok K. Sood 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: 11817524
    Abstract: Refractive optical element designs are provided for high geometric optical efficiency over a wide range of incident angles. To minimize Fresnel reflection losses, the refractive optical element designs employ multiple encapsulant materials, differing in refractive index. Concentrator photovoltaic subassemblies are formed by embedding a high efficiency photovoltaic device within the refractive optical element, along with appropriate electrical contacts and heat sinks. Increased solar electric power output is obtained by employing a single-junction III-V material structure with light-trapping structures.
    Type: Grant
    Filed: November 15, 2021
    Date of Patent: November 14, 2023
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Roger E. Welser, Ashok K. Sood
  • Patent number: 11674851
    Abstract: A high-performance Microbolometer that incorporates vanadium oxide (VOx) along with carbon nanotubes (CNTs) or graphene. This Microbolometer, which uses a microbridge comprising Si3N4 and VOx, provides low noise and high dynamic range longwave infrared (LWIR) band detection. Addition of CNTs/graphene provides a high level of performance [low 1/f noise, noise equivalent temperature difference (NETD), and thermal time constant] due to the high temperature coefficient of resistance (TCR) of these materials.
    Type: Grant
    Filed: August 11, 2021
    Date of Patent: June 13, 2023
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Ashok K. Sood, John W. Zeller
  • Patent number: 11609122
    Abstract: The present disclosure is a infrared sensor capable of being integrated into a IR focal plane array. It includes of a CMOS based readout circuit with preamplification, noise filtering, and row/column address control. Using either a microbolometer device structure with either a thermal sensing element of vanadium oxide or amorphous silicon, a nanocomposite is fabricated on top of either of these materials comprising aligned or unaligned carbon nanotube films with IR trans missive layer of silicon nitride followed by one to five monolayers of graphene. These layers are connected in series minimizing the noise sources and enhancing the NEDT of each film. The resulting IR sensor is capable of NEDT of less than 1 mK. The wavelength response is from 2 to 12 microns. The approach is low cost using a process that takes advantage of the economies of scale of wafer level CMOS.
    Type: Grant
    Filed: April 19, 2021
    Date of Patent: March 21, 2023
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Ashok K. Sood, Elwood J. Egerton
  • Patent number: 11404643
    Abstract: Ultraviolet (UV), Terahertz (THZ) and Infrared (IR) radiation detecting and sensing systems using graphene nanoribbons and methods to making the same. In an illustrative embodiment, the detector includes a substrate, single or multiple layers of graphene nanoribbons, and first and second conducting interconnects each in electrical communication with the graphene layers. Graphene layers are tuned to increase the temperature coefficient of resistance to increase sensitivity to IR radiation. Absorption over a wide wavelength range of 200 nm to 1 mm are possible based on the two alternative devices structures described within. These two device types are a microbolometer based graphene film where the TCR of the layer is enhanced with selected functionalization molecules. The second device structure consists of a graphene nanoribbon layers with a source and drain metal interconnect and a deposited metal of SiO2 gate which modulates the current flow across the phototransistor detector.
    Type: Grant
    Filed: March 16, 2020
    Date of Patent: August 2, 2022
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Elwood J. Egerton, Ashok K. Sood
  • Patent number: 11380808
    Abstract: A photovoltaic (PV) device having a quantum dot sensitized interface includes a first conductor layer and a second conductor layer. At least one of the conductor layers is transparent to solar radiation. A quantum dot (nanoparticle) sensitized photo-harvesting interface comprises a photo-absorber layer, a quantum dot layer and a buffer layer, placed between the two conductors. The absorber layer is a p-type material and the buffer layer is an n-type material. The quantum dot layer has a tunable bandgap to cover infrared (IR), visible light and ultraviolet (UV) bands of solar spectrum.
    Type: Grant
    Filed: September 28, 2020
    Date of Patent: July 5, 2022
    Assignee: Magnolia Solar, Inc.
    Inventors: Gopal G. Pethuraja, Roger E. Welser, Ashok K. Sood
  • Patent number: 11374187
    Abstract: Through selective incorporation of high carrier mobility graphene monolayers into low cost, NIR-sensitive SiGe detector layer structures, a device combining beneficial features from both technologies can be achieved. The SiGe in such hybrid SiGe/graphene detector devices serves as the NIR absorbing layer, or as the quantum dot material in certain device iterations. The bandgap of this SiGe layer where absorption of photons and photogeneration of carriers mainly takes place may be tuned by varying the concentrations of Ge in the SixGe1-x material. This bandgap and the thickness of this layer largely impact the degree and spectral characteristics of absorption properties, and thus the quantum efficiency or responsivity of the device. The main function and utility of the graphene monolayers, which are nearly transparent to incident light, is to facilitate the extraction and transport of electron and hole carriers from the SiGe absorbing layer through the device.
    Type: Grant
    Filed: April 22, 2020
    Date of Patent: June 28, 2022
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: John W. Zeller, Yash R. Puri, Ashok K. Sood
  • Patent number: 11367800
    Abstract: Optically-thin, quantum-structured solar cells incorporating III-V quantum wells or quantum dots have the potential to revolutionize the performance of photovoltaic devices. Enhanced spectral response characteristics have been widely demonstrated in both quantum well and quantum dot solar cells using a variety of different III-V materials. To fully leverage the extended spectral response of quantum-structured solar cells, new device designs are disclosed that can both maximize the current generating capability of the limited volume of narrow band gap material and minimize the unwanted carrier recombination that degrades the voltage output.
    Type: Grant
    Filed: February 26, 2018
    Date of Patent: June 21, 2022
    Assignee: Magnolia Solar, Inc.
    Inventors: Roger E. Welser, Ashok K. Sood
  • Patent number: 11340108
    Abstract: The use of silicon or vanadium oxide nanocomposite consisting of graphene deposited on top of an existing amorphous silicon or vanadium oxide microbolometer can result in a higher sensitivity IR detector. An IR bolometer type detector consisting of a thermally isolated nano-sized (<one micron feature size) electro-mechanical structure comprised of Si3N4, SiO2 thins films, suspended over a cavity with a copper thin film reflecting surface is described. On top of the suspended thin film is a nanostructure composite comprised of graphene monolayers, covered with various surface densities of VoXy or amorphous nanoparticles, followed by another graphene layer. The two conducting legs are connected to a readout integrated circuit (ROIC) fabricated on a CMOS wafer underneath. The nanostructure is fabricated after the completion of the ROIC process and is integrate able with the CMOS process.
    Type: Grant
    Filed: September 28, 2020
    Date of Patent: May 24, 2022
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Elwood J. Egerton, Ashok K. Sood
  • Patent number: 11177400
    Abstract: Refractive optical element designs are provided for high geometric optical efficiency over a wide range of incident angles. To minimize Fresnel reflection losses, the refractive optical element designs employ multiple encapsulant materials, differing in refractive index. Concentrator photovoltaic subassemblies are formed by embedding a high efficiency photovoltaic device within the refractive optical element, along with appropriate electrical contacts and heat sinks. Increased solar electric power output is obtained by employing a single-junction III-V material structure with light-trapping structures.
    Type: Grant
    Filed: September 18, 2017
    Date of Patent: November 16, 2021
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Roger E. Welser, Ashok K. Sood
  • Patent number: 10983010
    Abstract: The present disclosure is an infrared sensor capable of being integrated into a IR focal plane array. It includes of a CMOS based readout circuit with preamplification, noise filtering, and row/column address control. Using either a microbolometer device structure with either a thermal sensing element of vanadium oxide or amorphous silicon, a nanocomposite is fabricated on top of either of these materials comprising aligned or unaligned carbon nanotube films with IR transmissive layer of silicon nitride followed by one to five monolayers of graphene. These layers are connected in series minimizing the noise sources and enhancing the NEDT of each film. The resulting IR sensor is capable of NEDT of less than 1 mK. The wavelength response is from 2 to 12 microns. The approach is low cost using a process that takes advantage of the economies of scale of wafer level CMOS.
    Type: Grant
    Filed: May 28, 2019
    Date of Patent: April 20, 2021
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Ashok K. Sood, Elwood J. Egerton
  • Patent number: 10937914
    Abstract: Radiation detecting and sensing systems using graphene and methods of making the same are provided; including a substrate, a single or multiple layers of graphene nanoribbons, first and second conducting interconnects each in electrical communication with the graphene layers. Graphene layers are tuned to increase the temperature coefficient of resistance, increasing sensitivity to IR radiation. Absorption over a wide wavelength range (200 nm to 1 mm) is possible based on the three alternative devices structures described within. Devices can variously include (a) a microbolometer based graphene film where the TCR of the layer is enhanced with selected functionalization molecules, (b) graphene layers with a source and drain metal interconnect and a deposited metal of SiO2 gate which modulates the current flow across the phototransistor detector, and/or (c) tuned graphene layers layered on top of each other where a p-type layer and a n-type layer is created using a combination of oxidation and doping.
    Type: Grant
    Filed: May 20, 2019
    Date of Patent: March 2, 2021
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Elwood J. Egerton, Ashok K. Sood
  • Patent number: 10790399
    Abstract: A photovoltaic (PV) device having a quantum dot sensitized interface includes a first conductor layer and a second conductor layer. At least one of the conductor layers is transparent to solar radiation. A quantum dot (nanoparticle) sensitized photo-harvesting interface comprises a photo-absorber layer, a quantum dot layer and a buffer layer, placed between the two conductors. The absorber layer is a p-type material and the buffer layer is an n-type material. The quantum dot layer has a tunable bandgap to cover infrared (IR), visible light and ultraviolet (UV) bands of solar spectrum.
    Type: Grant
    Filed: April 2, 2018
    Date of Patent: September 29, 2020
    Assignee: Magnolia Solar, Inc.
    Inventors: Gopal G. Pethuraja, Roger E. Welser, Ashok K. Sood
  • Patent number: 10788364
    Abstract: The use of silicon or vanadium oxide nanocomposite consisting of graphene deposited on top of an existing amorphous silicon or vanadium oxide microbolometer can result in a higher sensitivity IR detector. An IR bolometer type detector consisting of a thermally isolated nano-sized (<one micron feature size) electro-mechanical structure comprised of Si3N4, SiO2 thins films, suspended over a cavity with a copper thin film reflecting surface is described. On top of the suspended thin film is a nanostructure composite comprised of graphene monolayers, covered with various surface densities of VoXy or amorphous nanoparticles, followed by another graphene layer. The two conducting legs are connected to a readout integrated circuit (ROIC) fabricated on a CMOS wafer underneath. The nanostructure is fabricated after the completion of the ROIC process and is integrate able with the CMOS process.
    Type: Grant
    Filed: July 8, 2019
    Date of Patent: September 29, 2020
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Elwood J. Egerton, Ashok K. Sood
  • Patent number: 10593883
    Abstract: Ultraviolet (UV), Terahertz (THZ) and Infrared (IR) radiation detecting and sensing systems using graphene nanoribbons and methods to making the same. In an illustrative embodiment, the detector includes a substrate, single or multiple layers of graphene nanoribbons, and first and second conducting interconnects each in electrical communication with the graphene layers. Graphene layers are tuned to increase the temperature coefficient of resistance to increase sensitivity to IR radiation. Absorption over a wide wavelength range of 200 nm to 1 mm are possible based on the two alternative devices structures described within. These two device types are a microbolometer based graphene film where the TCR of the layer is enhanced with selected functionalization molecules. The second device structure consists of a graphene nanoribbon layers with a source and drain metal interconnect and a deposited metal of SiO2 gate which modulates the current flow across the phototransistor detector.
    Type: Grant
    Filed: December 19, 2016
    Date of Patent: March 17, 2020
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Elwood J. Egerton, Ashok K. Sood
  • Patent number: 10345143
    Abstract: The use of silicon or vanadium oxide nanocomposite consisting of graphene deposited on top of an existing amorphous silicon or vanadium oxide microbolometer can result in a higher sensitivity IR detector. An IR bolometer type detector consisting of a thermally isolated nano-sized (<one micron feature size) electro-mechanical structure comprised of Si3N4, SiO2 thins films, suspended over a cavity with a copper thin film reflecting surface is described. On top of the suspended thin film is a nanostructure composite comprised of graphene monolayers, covered with various surface densities of VoXy or amorphous nanoparticles, followed by another graphene layer. The two conducting legs are connected to a readout integrated circuit (ROIC) fabricated on a CMOS wafer underneath. The nanostructure is fabricated after the completion of the ROIC process and is integrate able with the CMOS process.
    Type: Grant
    Filed: April 16, 2018
    Date of Patent: July 9, 2019
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Elwood J. Egerton, Ashok K. Sood
  • Patent number: 10302498
    Abstract: The present disclosure is an infrared sensor capable of being integrated into a IR focal plane array. It includes of a CMOS based readout circuit with preamplification, noise filtering, and row/column address control. Using either a microbolometer device structure with either a thermal sensing element of vanadium oxide or amorphous silicon, a nanocomposite is fabricated on top of either of these materials comprising aligned or unaligned carbon nanotube films with IR transmissive layer of silicon nitride followed by one to five monolayers of graphene. These layers are connected in series minimizing the noise sources and enhancing the NEDT of each film. The resulting IR sensor is capable of NEDT of less than 1 mK. The wavelength response is from 2 to 12 microns. The approach is low cost using a process that takes advantage of the economies of scale of wafer level CMOS.
    Type: Grant
    Filed: December 22, 2017
    Date of Patent: May 28, 2019
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Ashok K. Sood, Elwood J. Egerton
  • Patent number: 10297700
    Abstract: Radiation detecting and sensing systems using graphene and methods of making the same are provided; including a substrate, a single or multiple layers of graphene nanoribbons, first and second conducting interconnects each in electrical communication with the graphene layers. Graphene layers are tuned to increase the temperature coefficient of resistance, increasing sensitivity to IR radiation. Absorption over a wide wavelength range (200 nm to 1 mm) is possible based on the three alternative devices structures described within. Devices can variously include (a) a microbolometer based graphene film where the TCR of the layer is enhanced with selected functionalization molecules, (b) graphene layers with a source and drain metal interconnect and a deposited metal of SiO2 gate which modulates the current flow across the phototransistor detector, and/or (c) tuned graphene layers layered on top of each other where a p-type layer and a n-type layer is created using a combination of oxidation and doping.
    Type: Grant
    Filed: April 28, 2017
    Date of Patent: May 21, 2019
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Elwood J. Egerton, Ashok K. Sood
  • Patent number: 10281617
    Abstract: Durable hydrophobic antireflection structures for optical elements, optical windows, and front sheets of encapsulated photovoltaic and photonic devices are disclosed which can minimize reflection losses over the entire accessible portion of the solar spectrum simultaneously provide self-cleaning and finger-print-free surface. Reduced reflectance and self-cleaning surfaces are resulted from coating the front sheet of encapsulated device with combination of nonporous and porous nanostructured materials such as silicon dioxide nanorods and PTFE. Step-graded antireflection structures can exhibit excellent omnidirectional performance, significantly outperforming conventional quarter wavelength and low-high-low refractive index coatings. Methods of constructing nanostructured durable optical coatings with hydrophobic surfaces are disclosed that can cover large-area ridged and flexible substrates.
    Type: Grant
    Filed: July 25, 2016
    Date of Patent: May 7, 2019
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Gopal G. Pethuraja, Roger E. Welser, Yash R. Puri, Ashok K. Sood
  • Patent number: 10283657
    Abstract: The invention described herein details flexible, high-efficiency photovoltaic cells with nano-enhanced absorbers and ultra-low dark current. By extending infrared absorption, power conversion efficiencies in single-junction, nano-enhanced solar cells can potentially meet or even exceed the Shockley-Queisser limit. Novel device designs utilizing advanced band gap engineering are employed to suppress non-radiative recombination and expose the limiting radiative component of the dark current. Light trapping structures and new nanostructured absorber designs are also considered to maximize the creation and collection of photogenerated carriers. Flexible photovoltaic devices are fabricated using established full-wafer epitaxial liftoff processes. The innovative design described herein provides for light-weight and flexible photovoltaic sheets capable of achieving ultra-high conversion efficiencies over a wide range of operating conditions.
    Type: Grant
    Filed: March 14, 2014
    Date of Patent: May 7, 2019
    Assignee: Magnolia Optical Technologies, Inc.
    Inventors: Roger E. Welser, Ashok K. Sood
  • Patent number: 10090424
    Abstract: A method for fabricating a solar cell commences by bonding a first metal-coated substrate to a second metal-coated substrate to provide a bonded substrate. The bonded substrate is then coated with a first precursor solution to provide a coated bonded substrate. Finally, the procedure de-bonds the coated bonded substrate to provide a first solar cell device and a second solar cell device. A system for fabricating the solar cell comprises a first precursor solution deposition system containing a first precursor solution for deposition on a substrate, a first heating element for heating the substrate after deposition of the first precursor solution, a second precursor solution deposition system containing a second precursor solution for deposition on the substrate, and a second heating element for heating the substrate after deposition of the second precursor solution.
    Type: Grant
    Filed: July 7, 2016
    Date of Patent: October 2, 2018
    Assignee: Magnolia Solar, Inc.
    Inventors: Gopal G. Pethuraja, Roger E. Welser, Ashok K. Sood