Metal-oxide chemical sensor technology has been praised as a cheap and efficient method of detecting both reducing and oxidizing gases depending on the metal-oxide’s carrier type. The research conducted in this thesis explored methods of enhancing the sensitivity of an n-type metal-oxide material (indium tin oxide, ITO) to a volatile organic compound (VOC) through changes in both device and testing characteristics. Two methods of testing prototype sensors were developed which consisted of short and long-term exposure to ethanol at different temperatures and concentrations. Maximum sensitivity at 2000 ppm was achieved in devices with thin, annealed metal-oxide layers with a high temperature of operation; this sensitivity measurement was achieved using a prolonged exposure test with 100-nm of annealed ITO at an operating temperature of 360°C and yielded a sensitivity of 32.5%. A fabrication process consisting of two lift-off processes for the metal-oxide and contact metal was developed to create the prototype devices. Preliminary characterization on the metal-oxide materials confirmed its thickness, crystallinity / crystal structure, and grain size. In addition to the electrical tests, a future work chemical sensor was thermally and electrically simulated using SolidWorks and Silvaco Atlas, respectively; a proposed fabrication process of the device is also presented, along with a basic outline of future work experiments to further study sensitivity enhancements through other metal-oxide materials, noble catalytic metals, device architecture, and signal processing of proposed electrical testing.
Library of Congress Subject Headings
Chemical detectors--Calibration; Metallic oxides; Indium tin oxide; Volatile organic compounds
Microelectronic Engineering (MS)
Department, Program, or Center
Microelectronic Engineering (KGCOE)
Hughes, John F., "Sensitivity Enhancement of Metal-Oxide Chemical Sensors for Detection of Volatile Organic Compounds" (2017). Thesis. Rochester Institute of Technology. Accessed from
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