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.