Nanostructured metal oxide modification of a porous silicon interface for sensor applications: the question of water interaction, stability, platform diversity and sensitivity, and selectivity

(Invited) Metal Oxide Decorated Porous Silicon Interfaces for Sensor Applications: The Question of Water Interaction, Stability, Platform Diversity, Sensitivity, and Selectivity

“…The diffusion-linear interaction and diffusion-adsorption models are useful for providing insights 5,6,28 into the analyte gas-porous silicon interaction, however,the fit requires improvement. A comparison of different saturation response mechanisms suggests that measured and simulated saturation responses should include a log-log and derivative of the responses.…”

“…However, the range of interfaces also results in distinct disadvantages entailed, in part, by arrays of pore structures that cannot be easily reproduced despite their formation under similar silicon porosification 4 . Viable solutions to this drawback can be provided by a specific and reproducible micrometric pore structure whose response is regulated by metal oxide nanoparticle island (10-30 µ) sites deposited to the PSi interface and stabilized by direct in-situ nitration 5 .…”

“…These approaches and processes produce enhanced stability. The slow response of many PSi devices 1 due to limited mass transport and capillary condensation can be overcome using open 0.7-1.5 micron sized pores as this structure also reduces hysteresis 5 . Sensitivity is greatly improved by introducing highly active metal oxide nanostructured island sites to these open pores.…”

“…Sensitivity is greatly improved by introducing highly active metal oxide nanostructured island sites to these open pores. Linearity 5 , a problem with many semiconductor-based devices, is compensated by evaluating the first and second derivative of the sensor response. At this time it is possible to monitor two and sometimes three gases simultaneously with potential extension to additional gases with an array-based format relying on the combination of p and n-type silicon doping in concert with metal oxide nanostructure modified sensor interfaces [6][7][8][9] .…”