The ability to detect and quantify presence and concentration of unknown gasses is
sought for applications ranging from environmental monitoring to medical analysis. Metal
oxide based chemical sensing technology currently exists but the ability to provide a
compositional gas breakdown reliably within a short time frame is not readily available.
A very small sensor that can differentially identify the type and concentration of a gas is
required. Novel methods of creating low cost and easily tuned one and two-dimensional
gas sensing elements are explored. Tungsten trioxide has been thoroughly documented as
an electrochromic coating, but highly sensitive WO3 elements with beam and nanowire
structures have yet to be explored. Research of WO3 as a gas sensor encompasses three
major components: A suitable sensing chamber with accurate analyte gas flow control and
temperature control, a reliable method for WO3 deposition, and a high yield fabrication
process. This thesis explores all three of these technologies. Chapter two starts with
a summary of existing tungsten trioxide fabrication methods. An overview of WO3
processing follows. A comprehensive setup was designed and created to test the gas
sensing response of a series of metal oxide based resistive elements through conductimetric
analysis. Chapter three provides an in depth account of gas sensor test chamber design and
testing. Critical test chamber aspects such as temperature control, precise gas flow control,
highly efficient analyte gas switching and ease of use are presented. Chapter four outlines
WO3 electrodeposition and the fabrication of beam structures for testing, while chapter
five explores the templated electrodeposition of WO3 segments intercalated between gold
nanowire segments. Finally, chapter six provides a summary of the research presented in
this thesis as well as future directions and options available for further exploration of WO3
gas sensing elements. / Micro-Electro-Mechanical Systems (MEMS) and Nanosystems
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/999 |
| Date | 06 1900 |
| Creators | Murray, Andrew John |
| Contributors | Evoy, Stephane (Electrical and Computer Engineering), Brett, Michael (Electrical and Computer Engineering), Cadien, Ken (Chemical and Materials Engineering) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 189283052 bytes, application/pdf |
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