On Triboemission from the Sliding Contact of Si and Ge

Experimental research work is presented seeking a better understanding of triboemission of negatively-charged particles from sliding contacts. Previous research by the authors found significant emission of electrons from diamond-on-alumina, diamond-on-sapphire and alumina-on-alumina during sliding contact and after contact ceased, while no emission was detected from diamond-on-aluminum systems. This study explores negative-charge intensity from the semiconductors silicon and germanium when they are scratched by a diamond pin in high vacuum. While significant triboemission was always detected during the sliding contact, emission was undetectable when contact ended. Emission intensity is substantially higher for diamond-on-Si than for diamond-on-Ge. Decreasing emission is observed when the same wear track is scratched in repeated passes. These results are discussed with a focus on surface mechanisms that have been postulated to explain triboemission