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Dr. Douglas Buchanan

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Silicon-based, floating gate, polymer olfactory sensor platform

  1. ✦ Olfaction

  2. ‣Occurs when odorant molecules bind to specific sites on the olfactory receptors.

  3. ‣Receptors transmit signals to olfactory bulb and subsequently the brain.

  4. ‣Receptors are coded by large numbers of genes

  5. ‣Combination and overlapping sensitivities allow large range of orders to be identified

  6. ‣“Pattern recognition” that results from the brain’s translation of olfactory signals. 

  1. ✦ Sensor platform

  2. ‣Developed to mimic mammalian olfaction.

  3. ‣Combines polymer thin films (sensitive to groups of vapours) and a silicon chip array system  (Figure 1).

  4. ‣Large array (nxm) of silicon-based, commercially fabricated sensors onto which the polymers are electro-chemically deposited

  5. ‣Sensor outputs are translated into a digital signal on-chip and then “mapped” into a 2D olfactory image

  6. ‣Can be analysed using “pattern recognition” routines. 

  1. ✦ Results

  2. ‣Several polymers found to be sensitive to many different analytes.

  3. ‣Significant change in the sensor current (Figure 2)

  4. ‣Sensor polymer - polypyrrole (PPy) V

  5. ‣Very good distinction between water and methanol

  6. ‣Change in current: Water = x103, Methanol = x106 

  7. ‣Rate of change and final saturated current – distinguish vapour type and concentration

  8. ‣Demonstrates the feasibility and validity of sensor array platform.

Figure 1. Schematic diagram of the sensor array

  1. ✦ Commercial Development

  2. ‣Industrial interest from oil and gas sector

  3. ‣Develop sensor technology to distinguish between fuels; gasoline, diesel, kerosene, jet fuel, etc.

  4. ‣Several different polymers used with overlapping for sensitivities

  5. ‣Polymers deposited on test structure - resistance change (ΔR/R) was measured.

  6. ‣Preliminary results (Figure 3) – Principle Component Analysis - distinction several fuel vapours seen.


References


K. M. Ramesh, R. Shaun, T. Obaej, D. A. Buchanan, and M. S. Freund, "Chemical Diversity in Electrochemically Deposited Conducting Polymer-based Sensor Arrays," Sensors and Actuators B: Chemical, vol. 202, pp. 600-608, 2014.


M. O. Tareq, D. A. Buchanan, M. R. Kumar, M. S. Freund, and Ieee, "An Extended Floating Gate Gas Sensor using Polypyrrole as a sensing polymer," presented at the 2012 Sixth International Conference on Sensing Technology (Icst), Kolkata, India, 2012.


J. T. English, K. J. Cao, B. A. Deore, D. A. Buchanan, and M. S. Freund, "Floating gate field-effect transistors with broadly-responsive conducting polymers films as volatile organic compound sensors," presented at the The 90th Canadian Chemistry Conference and Exhibition, Winnipeg, Manitoba, Canada, 2007.


K. Cao, J. T. English, D. A. Buchanan, and M. S. Freund, "A Chemical Sensor Design Using a Standard CMOS Process," presented at the 13th Canadian Semiconductor Technology Conference (CSTC) Montreal Canada, 2007.


M. O. Tareq, "Floating Gate Metal-Oxide-Semiconductor Based Gas Sensor," M.Sc., Electrical and Computer Engineering, University of Manitoba, Winnipeg, MB Canada, 2014.

Interested in collaboration to investigate other commercial applications

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Figure 2. Single sensor response to water and methanol

Figure 3. Principle component analysis (PCA) - several different polymers - several fuel vapours. Clustering demonstrates the selectivity of the polymers.