Pumping electrons from chemical potential difference

Highlights: • The generators are made of only semiconducting or/and metallic electrodes. • Mechanical power is converted into electric power with a new working principle. • Conduction current and displacement current are generated internally. • The generators can be seamlessly integrated with other semiconductor devices. Electric generators can be categorized into four primary groups according to electrification processes: electromagnetic, electrostatic, piezoelectric and triboelectric generators. Electromagnetic generators produce conduction current based on Faraday's law. In contrast, electrostatic, piezoelectric and triboelectric generators create only displacement current internally. In this article, we report on a type of novel electric generators, which can be simply constructed using a pair of semiconducting or/and metallic electrodes with distinct chemical potentials. Electrons can diffuse from the higher into the lower chemical potential electrode when the electrodes are brought in contact and the diffused electrons are then discharged to the external circuit once the two electrodes are separated by mechanical power, accomplishing mechanical-electrical power conversion. In our generators, both displacement current and conduction current are generated.