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Search Publications by: Steve Semancik (Fed)

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Displaying 51 - 75 of 107

Template Fabrication of Protein-Functionalized Gold-Polypyrrole-Gold Segmented Nanowires

September 1, 2004
Author(s)
R M. Hernandez, Lee J. Richter, Stephen Semancik, Stephan J. Stranick, Thomas E. Mallouk
Gold nanowires containing protein-modified poly(pyrrole) (Ppy) junctions were synthesized electrochemically using porous aluminum oxide as a template. The effects of the conditions of electrochemical synthesis on Ppy growth and protein (avidin or

Mems-Based Embedded Sensor Virtual Components for SOC

June 24, 2004
Author(s)
Muhammad Afridi, Allen R. Hefner Jr., David W. Berning, Colleen E. Hood, Ankush Varma, Bruce Jacob, Stephen Semancik
The design and implementation of a monolithic MEMS-based (Micro Electro Mechanical Systems) gas sensor virtual component is described. A bulk micromachining technique is used to create suspended microhotplate structures. The thermal properties of the

Effects of Materials Chemistry and Morphology on Conductometric Sensor Signals

February 1, 2004
Author(s)
Douglas C. Meier, Stephen Semancik
Observation of conductance changes in material films upon their interactions with gas phase molecules is the basis of operation of the chemical microsensors being developed in the Chemical Sciences and Technology Laboratory at NIST. These interactions are

Porous Tin Oxide Nanostructured Microspheres for Sensor Applications

February 1, 2004
Author(s)
C Martinez, B Hockey, Christopher B. Montgomery, Stephen Semancik
There is a growing need to develop highly sensitive chemical sensors for applications such as military reconnaissance and toxic waste removal. A promising route for improving device performance is to use nanostructured materials (e.g. nanoparticles

Micro-Differential Scanning Calorimeter for Combustible Gas Sensing

January 1, 2004
Author(s)
Richard E. Cavicchi, G Poirier, N H. Tea, Muhammad Y. Afridi, David W. Berning, Allen R. Hefner Jr., John S. Suehle, Michael Gaitan, Stephen Semancik, Christopher B. Montgomery
A micron-scale differential scanning calorimeter (mDSC) has been produced on a silicon chip allowing for microscopic differential scanning calorimetry measurements on small samples. The device consists of a suspended rectangular microhotplate with sample

MEMS-based Embedded Sensor Virtual Components for SoC

November 25, 2003
Author(s)
Muhammad Afridi, Allen R. Hefner Jr., David W. Berning, Colleen E. Hood, Ankush Varma, Bruce Jacob, Stephen Semancik
Advancement in MEMS-based sensors brings a new challenge for system-on-a-chip (SoC) design integration where analog and digital circuits coexist on a common substrate with the actual sensing platform. Integration of these MEMS-based sensors into an SoC

Temperature-Dependent Materials Research with Micromachined Array Platforms

August 1, 2003
Author(s)
Stephen Semancik
This chapter describes the efficiency of studying temperature-dependent materials processing/property/performance relationships with MEMS-based microarrays. Varied types of microsamples (~ 100 m x 100 m in lateral dimension, and of thicknesses between ~ 10

Artificial Neural Networks Methods Applied to Conductometric Microhotplate Data for the Identification of the Type and Relative Concentration of Chemical Warfare Agents

April 1, 2003
Author(s)
Zvi Boger, Douglas C. Meier, Richard E. Cavicchi, Stephen Semancik
Response data from microhotplate (MHP) sensor arrays were measured for various chemical warfare (CW) agents at several concentrations. Efficient large-scale artificial neural networks (ANN) modeling has been evaluated as a method for the classification and

Temperature-Controlled MEMS Chemical Microsensors

March 13, 2003
Author(s)
Stephen Semancik, Richard E. Cavicchi, Douglas C. Meier, C J. Taylor, N O. Savage, M C. Wheeler
This paper describes MEMS microheater structures that have been employed in the development of chemical (gas) microsensors and other microanalytical components, such as preconcentrators and filters/separators. The role of microscale temperature control is

A Monolithic CMOS Microhotplate-based Gas Sensor System

December 1, 2002
Author(s)
Muhammad Afridi, John S. Suehle, Mona E. Zaghloul, David W. Berning, Allen R. Hefner Jr., Richard E. Cavicchi, Stephen Semancik, C B. Montgomery, C J. Taylor
A monolithic CMOS microhotplate-based conductance type gas sensor system is described. A bulk micromachining technique is used to create suspended microhotplate structures. The thermal properties of the microhotplates include a one-millisecond thermal time

A Monolithic Implementation of Interface Circuitry for CMOS Compatible Gas-Sensor System

July 1, 2002
Author(s)
Muhammad Afridi, John S. Suehle, Mona E. Zaghloul, David W. Berning, Allen R. Hefner Jr., Stephen Semancik, Richard E. Cavicchi
A monolithic CMOS micro-gas-sensor system, designed and fabricated in a standard CMOS process, is described. The gas-sensor system incorporates an array of four microhotplate-based gas-sensing structures. The system utilizes a thin film of tin-oxide (SnO 2

MEMS Device Platforms as Research Tools for Developing Improved Sensing Films

February 1, 2002
Author(s)
C J. Taylor, Richard E. Cavicchi, Stephen Semancik
Gas sensing characteristics of metal oxide films are dependent on the preparation method used in their fabrication. To optimize sensing film performance, one must understand how processing parameters influence composition andmicrostructure, and then

Sol-Gel Materials for Gas Phase Sensing Using Microhotplate Arrays

February 1, 2002
Author(s)
N O. Savage, Richard E. Cavicchi, Michael J. Tarlov, Stephen Semancik, J Greg Gillen
Sol-gel chemistry is used to create suspensions (sols) of small particles of materials such as metal oxides. These suspensions can be dried to a gel or powder or used in the sol form for coatings and thin films. One promising application of sol-gel derived

Micromachined Arrays as Sensor Platforms and Materials Research Tools

November 27, 2001
Author(s)
Stephen Semancik, Richard E. Cavicchi
We describe temperature-controlled elements called microhotplates which are formed by micromachining Si, as well as thin film deposition methods and interfacial phenomena, utilized to create low power, application-tunable microdevices for analyzing gases