This article reports on the resolution of mass detection by optical and capacitive methods in ambient atmosphere using very thin single-crystalline silicon microcantilevers. The detectable minimum mass by optical sensing increases slightly with decreasing cantilever size due to temperature fluctuation noise. Using capacitive detection, a detectable minimum mass of below 1× 10-14 g can be obtained using cantilevers with resonance frequencies of 78-80 kHz. From an experimental comparison, we find that the detectable minimum mass by capacitive detection is slightly smaller than that obtained by optical detection using a cantilever with resonant frequency of 78 kHz. Using theoretical modeling and experimental results relevant to gas adsorption-desorption to the sensor surface, it is found that the adsorption-desorption noise by gases with infinitesimal partial pressure in the air surrounding a cantilever significantly influences the resonance frequency fluctuation of the cantilever in the high resonance frequency region.
ASJC Scopus subject areas
- Physics and Astronomy(all)