Nongjian Tao

US Patent:

6737286, May 18, 2004

Filed:

Nov 27, 2002

Appl. No.:

10/305708

Inventors:

Nongjian Tao - Phoenix AZ
Salah Boussaad - Tempe AZ

Assignee:

Arizona Board of Regents - Tempe AZ

International Classification:

H01L 2166

US Classification:

438 17, 438 16, 438694, 438695, 438754

Abstract:

A method for forming atomic-scale contacts and atomic-scale gaps between two electrodes is disclosed. The method provides for applying a voltage between two electrodes in a circuit with a resistor. The applied voltage etches metal ions off one electrode and deposits the metal ions onto the second electrode. The metal ions are deposited on the sharpest point of the second electrode, causing the second electrode to grow towards the first electrode until an atomic-scale contact is formed. By increasing the magnitude of the resistor, the etching and deposition process will terminate prior to contact, forming an atomic-scale gap. The atomic-scale contacts and gaps formed according to this method are useful as a variety of nanosensors including chemical sensors, biosensors, hydrogen ion sensors, heavy metal ion sensors, magnetoresistive sensors, and molecular switches.

US Patent:

6784999, Aug 31, 2004

Filed:

Nov 13, 2001

Appl. No.:

10/031659

Inventors:

Nongjian Tao - Phoenix AZ
Salah Boussaad - Tempe AZ
Wenlue Huang - Miami FL

Assignee:

The Florida International University Board of Trustees - Miami FL

International Classification:

G01N 2100

US Classification:

356445

Abstract:

A device and method of detecting surface plasmon resonance for sensing molecules or conformational changes in molecules with high resolution and fast response time is disclosed. Light from a light source ( ) is focused through a prism onto a metal thin film ( ) on which sample molecules to be detected are adsorbed. The total internal reflection of the laser/incident light is collected with a differential position or intensity sensitive photo-detecting device instead of a single cell or an array of photo-detectors ( ) that are widely used in previous works. The ratio of the differential signal to the sum signal of the differential position or intensity sensitive photo-detecting device ( ) provides an accurate measurement of the shift in the surface plasmon resonance angle caused by the adsorption of molecules onto the metal films ( ) or by conformational changes in the adsorbed molecules. The present invention requires no numerical fitting to determine the resonant angle and the setup is compact and immune to background light, The methods and sensors of this invention can be used in numerous biological, biochemical, and chemical applications such as measuring subtle conformational changes in molecules and electron transfer reactions can be studied.

US Patent:

7030452, Apr 18, 2006

Filed:

Mar 4, 2004

Appl. No.:

10/795151

Inventors:

Nongjian Tao - Phoenix AZ, US
Salah Boussaad - Tempe AZ, US

Assignee:

Arizona Board of Regents - Tempe AZ

International Classification:

H01L 27/14
H01L 29/82
H01L 29/84

US Classification:

257414, 205775

Abstract:

A method for forming atomic-scale contacts and atomic-scale gaps between two electrodes is disclosed. The method provides for applying a voltage between two electrodes in a circuit with a resistor. The applied voltage etches metal ions off one electrode and deposits the metal ions onto the second electrode. The metal ions are deposited on the sharpest point of the second electrode, causing the second electrode to grow towards the first electrode until an atomic-scale contact is formed. By increasing the magnitude of the resistor, the etching and deposition process will terminate prior to contact, forming an atomic-scale gap. The atomic-scale contacts and gaps formed according to this method are useful as a variety of nanosensors including chemical sensors, biosensors, hydrogen ion sensors, heavy metal ion sensors, magnetoresistive sensors, and molecular switches.

US Patent:

7132837, Nov 7, 2006

Filed:

Aug 26, 2004

Appl. No.:

10/929134

Inventors:

Nongjian Tao - Scottsdale AZ, US

Assignee:

Arizona Board of Regents - Tempe AZ

International Classification:

G01R 27/08
G01N 27/453

US Classification:

324693, 204547

Abstract:

A conductivity measurement system measures conductivity of molecules. A substance to be measured is applied to the first and second electrodes. A potential is applied across the electrodes. A computer-controlled motion controller moves a first electrode relative to a second electrode in discrete steps. In a first step, the electrodes are brought together in physical contact to form a plurality of molecular junctions. The electrodes are separated by a first distance which breaks a first molecular junction. The electrodes are separated by a second distance which breaks a second molecular junction. A conductivity measure is taken at each step. The process of separating the electrodes continues until conductivity measure is zero. The conductivity of one molecule corresponds to a last non-zero conductivity measurement prior to a zero conductivity measurement.

US Patent:

7785001, Aug 31, 2010

Filed:

Nov 15, 2007

Appl. No.:

11/940953

Inventors:

Nongjian Tao - Scottsdale AZ, US
Francis Tsow - Tempe AZ, US

Assignee:

Arizona Board of Regents - Scottsdale AZ

International Classification:

G01K 11/22
G01N 25/00

US Classification:

374117, 374 45, 73579

Abstract:

An apparatus for sensing a change in environmental conditions is disclosed. The apparatus includes a coating or a wire between two surfaces that has a mechanical property changed as a result of a change in the environmental conditions. The change in the mechanical property of the coating or wire results in a change in a vibration characteristic of the apparatus, such as the frequency, phase, amplitude or quality factor. The change in the vibration characteristic can be used to determine the change in the environmental condition.

US Patent:

7879619, Feb 1, 2011

Filed:

Oct 6, 2006

Appl. No.:

11/544796

Inventors:

Tianwei Jing - Tempe AZ, US
Feimeng Zhou - Temple City CA, US
Nongjian Tao - Scottsdale AZ, US

International Classification:

G01N 21/41
G01N 21/01

US Classification:

436171, 250573, 250574, 250575, 250576, 356132, 356451, 422 8205, 422 8209, 422 8211, 436 46, 436 52, 436 86, 436 94, 436165

Abstract:

An apparatus for detecting one or more substances includes a radiation source emitting a beam of radiation and also includes a material capable of reflecting the beam of radiation with a first characteristic and capable of reflecting the beam of radiation with a second characteristic when the material interacts with the one or more substances. The apparatus also includes two or more radiation detectors to detect the first and second characteristics of the beam of radiation. A first one of the two or more radiation detectors is adjustably aligned to detect the first and second characteristics of the beam of radiation reflected from a first region of the material. A second one of the two or more radiation detectors is adjustably aligned to detect the first and second characteristics of the beam of radiation reflected from a second region of the material.

US Patent:

8215170, Jul 10, 2012

Filed:

Oct 23, 2006

Appl. No.:

11/568209

Inventors:

Nongjian Tao - Scottsdale AZ, US
Salah Boussaad - Wilmington DE, US

Assignee:

Arizona Board of Regents - Scottsdale AZ

International Classification:

G01N 29/12

US Classification:

73579, 73 32 A, 73 2401, 324633

Abstract:

A device for sensing a chemical analyte is disclosed. The device is comprised of a vibrating structure having first and second surfaces and having an associated resonant frequency and a wire coupled between the first and second surfaces of the vibrating structure, wherein the analyte interacts with the wire and causes a change in the resonant frequency of the vibrating structure. The vibrating structure can include a tuning fork. The vibrating structure can be comprised of quartz. The wire can be comprised of polymer. A plurality of vibrating structures are arranged in an array to increase confidence by promoting a redundancy of measurement or to detect a plurality of chemical analytes. A method of making a device for sensing a chemical analyte is also disclosed.

US Patent:

8416417, Apr 9, 2013

Filed:

Apr 24, 2009

Appl. No.:

12/989617

Inventors:

Kyle James Foley - Chandler AZ, US
Nongjian Tao - Scottsdale AZ, US

Assignee:

Arizona Board of Regents for and on behalf of Arizona State University - Scottsdale AZ

International Classification:

G01N 21/55

US Classification:

356445

Abstract:

Methods and apparatuses for imaging surface impedance.