The 9th International Conference on Surface Engineering (ICSE 2024)

The mechanism of surface friction at the microscopic scale has attracted significant research interest. It is believed that in semiconductor devices, the behavior of electron plays a key role in governing energy dissipation. Current research mainly focus on steady states, with limited evidence on how electron dynamics impact friction. Here, we demonstrate that friction in two-dimensional MoS₂/WS₂ heterostructures is enhanced by electron-hole radiative recombination dynamics. After rubbing against the sample, we observe that the topography remains unchanged, yet friction increases significantly due to an increased electron-hole recombination rate. Defects generate during rubbing, capturing electrons and accelerating the recombination rate from 0.07 ns^-1 to 0.13 ns^-1. Density functional theory reveals that the increase of friction is due to the change corrugation of potential energy surface caused by defect, leading to the direct modulation of friction by electron dynamics. Our findings provide new avenues for exploring the microscopic origins of friction from the perspective of electron dynamics.

exciton lifetime,friction,heterostructures,defects