Patents by Inventor April S. Brown
April S. Brown 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).
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Patent number: 10407716Abstract: A sensor comprising a semiconductor layer having a two dimensional electron gas (2DEG) and an oxide layer in electronic contact with the semiconductor layer is provided. A method of detecting an analyte molecule using such sensor is also provided.Type: GrantFiled: March 13, 2015Date of Patent: September 10, 2019Assignee: Duke UniversityInventors: April S. Brown, Maria Losurdo, Chris Dwyer
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Patent number: 9970897Abstract: A van der Pauw (VDP) sensor comprising an electronic circuit electrically coupled to a surface, the surface comprising a type III-V material, and the electronic circuit measuring a sheet resistivity of the surface using a VDP technique. The VDP sensor may further comprise a macromolecule, such as a porphyrin, an oligonucleotide, a protein, a polymer or a combination thereof in contact with the surface. The VDP sensors may be arranged in an array of similar or different sensors. An electronic circuit electrically coupled to a type III-V material having a two-dimensional electron gas, such as InAs or InN, the electronic circuit measuring an electrical property of the type III-V material having a two-dimensional electron gas.Type: GrantFiled: June 16, 2009Date of Patent: May 15, 2018Assignee: Duke UniversityInventors: Michael A. Garcia, Scott D. Wolter, April S. Brown, William V. Lampert
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Patent number: 9958442Abstract: A sensor comprising an electronic circuit electrically coupled to a type III-V semiconductor material, for example indium arsenide (InAs) and an antibody contacting the type III-V semiconductor material. The sensor produces measurable N changes in the electrical properties of the semiconductor upon antibody-antigen binding events. Electrical properties measurable by the electronic device may include resistivity, capacitance, impedance, and inductance. A method of detecting an antigen using sensors of the invention. A method of detecting a reaction of an analyte to a stimulus using sensors of the invention. Sensor arrays comprising multiple sensors of the invention.Type: GrantFiled: February 11, 2010Date of Patent: May 1, 2018Assignee: Duke UniversityInventors: R. Michael Angelo, April S. Brown, Scott Wolter, William V. Lampert
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Publication number: 20170088883Abstract: A sensor comprising a semiconductor layer having a two dimensional electron gas (2DEG) and an oxide layer in electronic contact with the semiconductor layer is provided. A method of detecting an analyte molecule using such sensor is also provided.Type: ApplicationFiled: March 13, 2015Publication date: March 30, 2017Applicant: Duke UniversityInventors: April S. Brown, Maria Losurdo, Chris Dwyer
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Patent number: 8471294Abstract: GaN-based heterojunction field effect transistor (HFET) sensors are provided with engineered, functional surfaces that act as pseudo-gates, modifying the drain current upon analyte capture. In some embodiments, devices for sensing nitric oxide (NO) species in a NO-containing fluid are provided which comprise a semiconductor structure that includes a pair of separated GaN layers and an AlGaN layer interposed between and in contact with the GaN layers. Source and drain contact regions are formed on one of the GaN layers, and an exposed GaN gate region is formed between the source and drain contact regions for contact with the NO-containing fluid. The semiconductor structure most preferably is formed on a suitable substrate (e.g., SiC). An insulating layer may be provided so as to cover the semiconductor structure. The insulating layer will have a window formed therein so as to maintain exposure of the GaN gate region and thereby allow the gate region to contact the NO-containing fluid.Type: GrantFiled: November 18, 2010Date of Patent: June 25, 2013Assignee: Duke UniversityInventors: Michael A. Garcia, Scott D. Wolter, April S. Brown, Joseph Bonaventura, Thomas F. Kuech
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Publication number: 20120122736Abstract: A sensor comprising an electronic circuit electrically coupled to a type III-V semiconductor material, for example indium arsenide (InAs) and an antibody contacting the type III-V semiconductor material. The sensor produces measurable N changes in the electrical properties of the semiconductor upon antibody-antigen binding events. Electrical properties measurable by the electronic device may include resistivity, capacitance, impedance, and inductance. A method of detecting an antigen using sensors of the invention. A method of detecting a reaction of an analyte to a stimulus using sensors of the invention. Sensor arrays comprising multiple sensors of the invention.Type: ApplicationFiled: February 11, 2010Publication date: May 17, 2012Applicant: DUKE UNIVERSITYInventors: R. Michael Angelo, April S. Brown, Scott Wolter, William V. Lampert
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Publication number: 20110199102Abstract: A van der Pauw (VDP) sensor comprising an electronic circuit electrically coupled to a surface, the surface comprising a type III-V material, and the electronic circuit measuring a sheet resistivity of the surface using a VDP technique. The VDP sensor may further comprise a macromolecule, such as a porphyrin, an oligonucleotide, a protein, a polymer or a combination thereof in contact with the surface. The VDP sensors may be arranged in an array of similar or different sensors. An electronic circuit electrically coupled to a type III-V material having a two-dimensional electron gas, such as InAs or InN, the electronic circuit measuring an electrical property of the type III-V material having a two-dimensional electron gas.Type: ApplicationFiled: June 16, 2009Publication date: August 18, 2011Inventors: Michael A. Garcia, Scott D. Wolter, April S. Brown, William V. Lampert
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Publication number: 20110097837Abstract: GaN-based heterojunction field effect transistor (HFET) sensors are provided with engineered, functional surfaces that act as pseudo-gates, modifying the drain current upon analyte capture. In some embodiments, devices for sensing nitric oxide (NO) species in a NO-containing fluid are provided which comprise a semiconductor structure that includes a pair of separated GaN layers and an AlGaN layer interposed between and in contact with the GaN layers. Source and drain contact regions are formed on one of the GaN layers, and an exposed GaN gate region is formed between the source and drain contact regions for contact with the NO-containing fluid. The semiconductor structure most preferably is formed on a suitable substrate (e.g., SiC). An insulating layer may be provided so as to cover the semiconductor structure. The insulating layer will have a window formed therein so as to maintain exposure of the GaN gate region and thereby allow the gate region to contact the NO-containing fluid.Type: ApplicationFiled: November 18, 2010Publication date: April 28, 2011Inventors: Michael A. Garcia, Scott D. Wolter, April S. Brown, Joseph Bonaventura, Thomas F. Kuech
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Patent number: 7868354Abstract: GaN-based heterojunction field effect transistor (HFET) sensors are provided with engineered, functional surfaces that act as pseudo-gates, modifying the drain current upon analyte capture. In some embodiments, devices for sensing nitric oxide (NO) species in a NO-containing fluid are provided which comprise a semiconductor structure that includes a pair of separated GaN layers and an AlGaN layer interposed between and in contact with the GaN layers. Source and drain contact regions are formed on one of the GaN layers, and an exposed GaN gate region is formed between the source and drain contact regions for contact with the NO-containing fluid. The semiconductor structure most preferably is formed on a suitable substrate (e.g., SiC). An insulating layer may be provided so as to cover the semiconductor structure. The insulating layer will have a window formed therein so as to maintain exposure of the GaN gate region and thereby allow the gate region to contact the NO-containing fluid.Type: GrantFiled: November 8, 2007Date of Patent: January 11, 2011Assignee: Duke UniversityInventors: Michael A. Garcia, Scott D. Wolter, April S. Brown, Joseph Bonaventura, Thomas F. Kuech
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Publication number: 20080203431Abstract: GaN-based heterojunction field effect transistor (HFET) sensors are provided with engineered, functional surfaces that act as pseudo-gates, modifying the drain current upon analyte capture. In some embodiments, devices for sensing nitric oxide (NO) species in a NO-containing fluid are provided which comprise a semiconductor structure that includes a pair of separated GaN layers and an AlGaN layer interposed between and in contact with the GaN layers. Source and drain contact regions are formed on one of the GaN layers, and an exposed GaN gate region is formed between the source and drain contact regions for contact with the NO-containing fluid. The semiconductor structure most preferably is formed on a suitable substrate (e.g., SiC). An insulating layer may be provided so as to cover the semiconductor structure. The insulating layer will have a window formed therein so as to maintain exposure of the GaN gate region and thereby allow the gate region to contact the NO-containing fluid.Type: ApplicationFiled: November 8, 2007Publication date: August 28, 2008Inventors: Michael A. Garcia, Scott D. Wolter, April S. Brown, Joseph Bonaventura, Thomas F. Kuech
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Patent number: 5489549Abstract: High speed Group III-Sb materials are n-doped in a molecular beam epitaxy process by forming a superlattice with n-doped strained layers of a Group III-V compound upon Group III-Sb base layers. The base layers have lower conduction band energy levels than the strained layers, and allow doping electrons from the strained layers to flow into the base layers. The base layers preferably comprise Al.sub.x Ga.sub.1-x Sb, while the strained layers preferably comprise a binary or ternary compound such as Al.sub.y Ga.sub.1-y As having a single Group V component, where x and y are each from 0 to 1.0. The strained layers can be n-doped with silicon or tin, which would produce p-type doping if added directly to the base layers.Type: GrantFiled: April 14, 1994Date of Patent: February 6, 1996Assignee: Hughes Aircraft CompanyInventors: Thomas C. Hasenberg, April S. Brown, Lawrence E. Larson
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Patent number: 5420442Abstract: High speed Group III-Sb materials are n-doped in a molecular beam epitaxy process by forming a superlattice with n-doped strained layers of a Group III-V compound upon Group III-Sb base layers. The base layers have lower conduction band energy levels than the strained layers, and allow doping electrons from the strained layers to flow into the base layers. The base layers preferably comprise Al.sub.x Ga.sub.1-x Sb, while the strained layers preferably comprise a binary or ternary compound such as Al.sub.y Ga.sub.1-y As having a single Group V component, where x and y are each from 0 to 1.0. The strained layers can be n-doped with silicon or tin, which would produce p-type doping if added directly to the base layers.Type: GrantFiled: April 5, 1994Date of Patent: May 30, 1995Assignee: Hughes Aircraft CompanyInventors: Thomas C. Hasenberg, April S. Brown, Lawrence E. Larson
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Patent number: 5322808Abstract: A donor layer (17) including an undoped wide bandgap material (14) and an n-type dopant (16) is deposited on a substrate (12) by molecular beam epitaxy (MBE) at a first temperature which is high enough for optimal growth of the donor layer (17). The dopant (16) is silicon or another material which exhibits surface segregation in the wide bandgap material (14) at the first temperature. An undoped spacer layer (18) of the wide bandgap material is deposited on the donor layer (17) at a second temperature which is sufficiently lower than the first temperature that surface segregation of the dopant material from the donor layer (17) into the spacer layer (18) is substantially suppressed. A channel layer (20) of a narrow bandgap material is formed on the spacer layer (18) at a third temperature which is higher than the second temperature and selected for optimal growth of the channel layer (20).Type: GrantFiled: February 19, 1993Date of Patent: June 21, 1994Assignee: Hughes Aircraft CompanyInventors: April S. Brown, Joseph A. Henige, Mark Lui, Loi Nguyen, Robert A. Metzger, William E. Stanchina