THERMAL AND AMBIENT-INDUCED DEFLECTIONS OF SCANNING FORCE MICROSCOPE CANTILEVERS

The deflection of scanning force microscope cantilevers, metal coated on one side, is significantly influenced by both thermal heating and v ariations in relative humidity. For constant relative humidity, the de flection of the cantilever drifts due to laser heating and eventually reaches a steady-state value. For a thermally stabilized cantilever, t he deflection varies linearly with relative humidity. Exposure to othe r vapors, such as mercury, changes the inherent deflection of the cant ilever. Relative amounts of adsorbates on the cantilever can be estima ted from shifts in the cantilever resonance frequency with picogram ma ss resolution. The cantilever deflection as well as changes in resonan ce frequency due to vapor adsorption can be used as basis for novel ch emical sensors.