Tribovoltaic nanogenerators based on n-n and p-p semiconductor homojunctions

Abstract

Tribovoltaic nanogenerators (TVNGs) usually consist of two heterogeneous materials with disparate Fermi levels. However, TVNGs based on two same semiconductors with uniformed Fermi levels have been rarely reported, as they are believed to lack the sufficient potential difference necessary to drive tribo-induced carriers’ separation and collection, resulting in minimal or negligible electricity production. Here, tribovoltaic nanogenerators based on two homojunction semiconductors (H-TVNGs) with the same doping concentration are proposed and designed. The H-TVNGs were demonstrated to be driven by abundant surface states introduced through laser cutting at the slider boundaries and surfaces, which further lead to the bending of interface energy bands. Upon two sliders of different sizes (with different degrees of band bending) come into contact, the built-in electric field at the interface will be established and drive tribo-induced carriers, leading to the production of a direct-current (DC) electrical signal. The performance of H-TVNGs could be effectively amplified or regulated by many factors, including laser cutting power, semiconductor surface roughness, slider shape, and the interface media, etc. These compelling findings reveal innovative physics in tribovoltaic effect, offer special insights for designing high-performance TVNGs, and provide effective strategies for device output optimization.