Competitive Mechanism between Interfacial Electric Field and Built-In Electric Field for Silicon-Based Tribovoltaic Effect

The tribovoltaic effect raises an emerging semiconductor energy technology and silicon-based tribovoltaic nanogenerator (Si-TVNG) has aroused great attentions. However, the electrical output of Si-TVNG is extremely unstable due to its complicated mechanism. Here, a competitive mechanism between the built-in electric field (BEF) and the interfacial electric field (IEF) is proposed to determine the current direction and magnitude of the Si-TVNG. The results indicate that the natural oxide layer, load pressure, and resistivity of Si significantly affect the IEF and BEF. The natural oxide layer can store surface charges by contact electrification, resulting in a IEF dominant carriers transport process. Conversely, lower resistivity and higher load pressure can reduce the contact resistance, thereby decreasing the surface charges caused by contact electrification and leading to a BEF dominant carrier transport process. This work contributes to deeper understandings of the tribovoltaic effect and further clarifies the theoretical mechanisms of carrier excitation and directional transport. This work proposes a competitive mechanism between the built-in electric field (BEF) and the interfacial electric field (IEF) to determine the current direction and magnitude of the silicon-based tribovoltaic nanogenerator. It contributes to deeper understandings of the tribovoltaic effect and further clarifies the theoretical mechanisms of carrier excitation and directional transport.image