Separation and Quantum Tunneling of Photo-generated Carriers Using a Tribo-Induced Field

Tribo-induced potential at a metal-insulator-semiconductor sliding junction results in very high interfacial electric field E (similar to 10(7)-10(8) V/m). Such fields are used to separate photo-generated electron-hole pairs that transport through the junction via quantum tunneling. We show that this phenomenon can generate direct current with high current density J. The strong synergetic effect between the photo-excitation and the interfacial electronic excitation at the MIS sliding contact boosts the photocurrent output in Si-based Schottky solar cell by 50 times and the triboelectric power output by 28 times. Charge relaxation dynamics calculations agree well with conductive atomic force microscopy results and show the coupling effect between the photo- and the tribo-induced electric fields. Experimental observation of the tribo-photovoltaic effect provides new fundamental understanding of electromechanical coupling, and thus offers a new direction for future solar-mechanical energy co-harvesting.