Session Q21: THz and Impedance Spectroscopy

11:15 AM–2:15 PM, Wednesday, March 23, 2011
Room: D161

Sponsoring Unit: GIMS
Chair: Rachael Floyd, Janis Research Company

Abstract ID: BAPS.2011.MAR.Q21.7

Abstract: Q21.00007 : A high performance humidity sensor based on dielectric detection with a novel coaxial nanostructure

12:27 PM–12:39 PM

Preview Abstract MathJax On | Off   Abstract  

Authors:

  Dong Cai
    (Boston College)

  Huaizhou Zhao
    (Boston College)

  Binod Rizal
    (Boston College)

  Timothy Kirkpatrick
    (Boston College)

  Zhifeng Ren
    (Boston College)

  Michael J. Naughton
    (Boston College)

  Thomas C. Chiles
    (Boston College)

High throughput coaxial nanocavity arrays are developed by overlaying porous Al$_{2}$O$_{3}$ and Al layers on vertically aligned carbon nanotube arrays. The porosity of Al$_{2}$O$_{3}$ was electrochemically characterized. The dielectric properties of the nanocoax structure were measured by impedance spectroscopy, from 10 mHz to 1 MHz. The capacitance of the sensor responded to humidity applied to the chip, $i.e.$ soaking the array with water increased the capacitance by 130{\%}. The detection mechanism was established for sensing changes to the dielectric constant due to adsorbed moisture in the porous Al$_{2}$O$_{3}$ coax annulus, with theoretical calculations based on~the Clausius-Mossotti equation~in agreement with the measurements.~ Highly sensitive humidity detection was demonstrated by applying relative humidity between 0.1{\%} and 100{\%}, with a power-law response, \textit{RH}$\sim x^{\alpha }$. This nanocoaxial structure thus offers the possibility of unprecedented performance of porous Al$_{2}$O$_{3}$-mediated capacitancer sensing for humidity detection.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.Q21.7