Triboelectric junction: a model for dynamic metal-semiconductor contacts

Static metal-semiconductor contacts are classified into Ohmic contacts and Schottky contacts. As for dynamic metal-semiconductor contacts, the in-depth mechanism remains to be studied. We here define a "triboelectric junction" model for analyzing dynamic metal-semiconductor contacts, where a space charge region induced by the triboelectric effect dominates the electron-hole separation process. Through theoretical analysis and experiments, we conclude that the triboelectric junction influences the electric output in two aspects: (1) the junction direction determines the output polarity; (2) the junction strength determines the output magnitude. Both the junction direction and junction strength are closely related to the electron-affinity difference between the contact metal and semiconductor. A "triboelectric junction" is a space charge region induced by the triboelectric effect, dominating the electron-hole separation process in dynamic semiconductor-based contacts.