| 摘要 |
A resonant MEMS device that detects photons, particles and small forces including atomic forces is disclosed. The device comprises a planar substrate 1, two electrodes 2 and 3 on top of the substrate, a resonant micro-electromechanical (MEMS) structure 6, such as a cantilever, anchored to first electrode 2 and arranged above the second electrode 3 separated from this electrode with an ultrathin transition layer 5. The resonant MEMS structure is working at its natural resonant frequency. The resonant oscillation of the cantilever can be initiated by applying AC voltage with frequency equaling the resonant frequency of the MEMS structure. A constant voltage is applied between the cantilever and the second electrode. The cantilever oscillates at very small amplitude ranging from fewÅngstrom (Å) to several nm. During operation, a constant component of the electrical current is measured between the cantilever and the second electrode 3. The electrical current is a tunnelling current described by quantum mechanical probability with which the electrons can tunnel through the transition layer. The thickness of the transition layer is selected so that at no resonance the constant component of the electrical current is about zero and at resonance the DC electrical current has non-zero value and reaches its maximum. When the cantilever interacts with photons, particles or atoms on surfaces then the MEMS device measures their energies using change in the DC tunnelling current and shift of resonant frequency.
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