Intrinsically biased, resonant NEMS-MEMS oscillator and the second law of thermodynamics

An experimentally testable NEMS-MEMS resonant cantilever oscillator is examined theoretically for compliance with the second law of thermodynamics. The device consists of a p-n semiconductor parallel-plate capacitor, with one plate fixed (p-doped) and the other (n-doped) mounted on a flexible double cantilever spring. The built-in potential across the n-p depletion region is expressed as an electric field between the capacitor plates, providing negative pressure capable of closing the plates. For matched electrical and mechanical time constants (τe≃τm), the device is predicted to execute steady-state electromechanical oscillation, powered solely by the p-n diodic electric field, thereby challenging the Kelvin-Planck formulation of the second law. Prospects for laboratory tests are discussed.