Stephen G Howell

US Patent:

7550071, Jun 23, 2009

Filed:

Feb 25, 2005

Appl. No.:

11/065894

Inventors:

Shawn M. Dirk - Albuquerque NM, US
Stephen W. Howell - Albuquerque NM, US
David R. Wheeler - Albuquerque NM, US

Assignee:

Sandia Corporation - Albuquerque NM

International Classification:

C25D 7/12
C25D 11/00
C25B 3/00
C25B 3/12

US Classification:

205457, 205157, 205317, 205463

Abstract:

Methods are described for the electrochemical assembly of organic molecules on silicon, or other conducting or semiconducting substrates, using iodonium salt precursors. Iodonium molecules do not assemble on conducting surfaces without a negative bias. Accordingly, the iodonium salts are preferred for patterning applications that rely on direct writing with negative bias. The stability of the iodonium molecule to acidic conditions allows them to be used with standard silicon processing. As a directed assembly process, the use of iodonium salts provides for small features while maintaining the ability to work on a surface and create structures on a wafer level. Therefore, the process is amenable for mass production. Furthermore, the assembled monolayer (or multilayer) is chemically robust, allowing for subsequent chemical manipulations and the introduction of various molecular functionalities for various chemical and biological applications.

US Patent:

7867754, Jan 11, 2011

Filed:

Apr 11, 2007

Appl. No.:

11/786757

Inventors:

Fred E. Regnier - West Lafayette IN, US
Ronald George Reifenberger - West Lafayette IN, US
Halina Dorota Inerowicz - West Lafayette IN, US
Stephen Wayne Howell - Albuquerque NM, US

Assignee:

Purdue Research Foundation - West LaFayette IN

International Classification:

C12M 1/34
C12M 3/00

US Classification:

4352871, 435 71, 4352831, 4352872, 4352887, 436164, 422 681, 422 8205

Abstract:

Method and device for detection of analytes, particularly biohazards. A microarray containing immobilized sensing molecules captures complementary analytes on a redundant patterned substrate. Pattern analysis is performed using a computer algorithm.

US Patent:

8302458, Nov 6, 2012

Filed:

Apr 21, 2008

Appl. No.:

12/106734

Inventors:

Kazi Zulfiqur Ali Hassan - Huntsville AL, US
William M. Cost - Hartselle AL, US
Curtis D. Mowry - Albuquerque NM, US
Michael P. Siegal - Albuquerque NM, US
Alex Robinson - Albuquerque NM, US
Joshua J. Whiting - Los Lunas NM, US
Stephen W. Howell - Albuquerque NM, US

Assignee:

Parker-Hannifin Corporation - Cleveland OH

International Classification:

G01N 30/02
G01N 30/76
G01N 29/02

US Classification:

73 234, 73 2401, 73 2406

Abstract:

A portable analytical system for detecting organic chemicals in water comprising a miniature preconcentrator and a SAW detector, the latter being characterized by a nanoporous carbon coating that provides improved response compared to prior art polymer coatings, particularly when detecting low concentrations of trihalomethane chemicals, such as chloroform and bromoform.

US Patent:

20200350356, Nov 5, 2020

Filed:

Jul 16, 2020

Appl. No.:

16/930520

Inventors:

- Albuquerque NM, US
Michael Goldflam - Albuquerque NM, US
Isaac Ruiz - Albuquerque NM, US
David W. Peters - Albuquerque NM, US
Stephen W. Howell - Bloomington IN, US

International Classification:

H01L 27/146
H01L 31/0296
H01L 31/0304
H01L 31/0352
H01L 27/16
H01L 37/02

Abstract:

A monolithically integrated, tunable infrared pixel comprises a combined broadband detector and graphene-enabled tunable metasurface filter that operate as a single solid-state device with no moving parts. Functionally, tunability results from the plasmonic properties of graphene that are acutely dependent upon the carrier concentration within the infrared. Voltage induced changes in graphene's carrier concentration can be leveraged to change the metasurface filter's transmission thereby altering the “colors” of light reaching the broadband detector and hence its spectral responsivity. The invention enables spectrally agile infrared detection with independent pixel-to-pixel spectral tunability.

US Patent:

20190219747, Jul 18, 2019

Filed:

Jan 16, 2018

Appl. No.:

15/872293

Inventors:

- Albuquerque NM, US
Michael Goldflam - Albuquerque NM, US
Stephen W. Howell - Albuquerque NM, US
David W. Peters - Albuquerque NM, US
Isaac Ruiz - Albuquerque NM, US
Paul Davids - Albuquerque NM, US

International Classification:

G02B 5/20
G02B 5/26
G01N 21/17
G02B 1/04

Abstract:

An actively tunable optical filter can control the amplitude of reflected infrared light. The filter exploits the dependence of the excitation energy of plasmons in a continuous and unpatterned sheet of graphene, on the Fermi-level,which can be controlled by conventional electrostatic gating. An exemplary filter enables simultaneous modification of two distinct spectral bands whose positions are dictated by the device geometry and graphene plasmon dispersion. Within these bands, the reflected amplitude can be varied by over 15% and resonance positions can be shifted by over 90 cm. Electromagnetic simulations verify that tuning arises through coupling of incident light to graphene plasmons by a nanoantenna grating structure. Importantly, the tunable range is determined by a combination of graphene properties, device structure, and the surrounding dielectrics, which dictate the plasmon dispersion. Thus, the underlying design is applicable across a broad range of infrared frequencies.

US Patent:

20160172527, Jun 16, 2016

Filed:

Feb 8, 2016

Appl. No.:

15/017847

Inventors:

- Albuquerque NM, US
Stephen W. Howell - Albuquerque NM, US
David W. Peters - Albuquerque NM, US
Paul Davids - Albuquerque NM, US
Eric A. Shaner - Rio Rancho NM, US

International Classification:

H01L 31/113
H01L 31/0232

Abstract:

An interdigitated nanoelectrode grating functions both as an absorption-enhancing sub-wavelength antenna and to minimize the distance between electron-hole creation and current collection so as to enhance photodetection schemes based upon active layers comprising two-dimensional semiconducting materials.