In the pursuit of an alternative fuel source, hydrogen gas appears to have the best potential. All hydrogen gas related processes require accurate monitoring for leaks during the storage, transportation and usage. The problem that arises with the use of hydrogen is its tendency to leak along with being highly explosive at 4-vol%. Most of the current metal oxide based chemi-resitors in use as detectors operate at elevated temperature (above 100 degree Celsius) in order to aid their sensor’s response kinetics. This becomes a safety concern due to its proximity to the highly explosive hydrogen gas. The search for low temperature sensitive hydrogen sensing device is at the forefront of our research endeavor.

SnO2 was deposited on SiO2/Si substrates through the method of pulse laser deposition (PLD) to form thin film. Through the process of nanosecond pulse laser interference irradiation of the thin film, successfully architectured SnO2 nanoarrays were developed. These nanowire-like SnO2 structures fabricated were uniformly distributed along the surface of the substrate. Dimensions of the nanostructure were obtained through Atomic Force Microscopy (AFM) and Scanning Electron Microscopy. Results obtained illustrate that the nanoarray’s nanowires were ~8 nm in cross-sectional height and tens of microns in length. Both thin film and nanoarray were then incorporated into MEMS device. Tests of chemi-resistors were conducted at room temperature within the concentration limits of 300 to 9000 ppm under dynamic condition, simulating the actual environments of exposure. In comparison to SnO2 thin film, the nanoarray illustrates a significantly larger electrical response upon exposure to concentrations as minimal as 600 ppm. Nanoarray exhibited a (drop in resistances by 2 orders of magnitude) 150 fold increase in electrical response in comparison to that of the thin film.

SnO2 nanoarray incorporation into the MEMs platform has successfully produced a low temperature hydrogen sensor. The performance of the nanoarray showed promising applicability due to it fast response time, high electrical response and its robustness. Theoretical models of the depletion layer and the diffusive characteristic within SnO2 were developed in order to exemplify the combined sensing mechanism due to the nanoarray’s geometry. This research endeavor therefore combines aspect of interdisciplinary materials design and integration alongside MEMS design, experimental conduction and modeling of device mechanism in the development a gas detector.