650 research outputs found
On The Strength of Tribo-Emission in Sliding of Diamond on Single Crystal Silicon
Triboemission is a phenomenon associated with the sliding of variety of
materials. The phenomenon is thought to be related to wear of diamond tools
used in precision machining of semiconductors. As such, the physics of emission
has recently acquired importance. Many researchers studied emission during
scratching of solid surfaces. They observed that the intensity of tribo-induced
emission of the electrons, ions, and photons decrease in the order:
insulator>semiconductor> conductor. Many experiments conducted to compare the
emission of negatively-charged particles in case of the semiconductors Si with
that from selected insulators have reported a clear decreasing trend of the
tribo-emission intensity as contact progressed over the same wear track for
diamond-on-Si. Despite that all of these experiments were performed in vacuum,
the origin of the weak signals and the decrease of signal strength in the case
of Si centred on the presence of dielectric silicon oxide films formed in air
during surface preparation or because of the samples being of mono-crystalline
nature. This paper offers an alternative explanation to the behaviour of
tribo-emitted particles based on the pressure induced
semi-conductor-to-metallic phase transformation that takes place in Si during
sliding. It is shown that due to repeated sliding, the wear tracks experience a
semiconductor-to- metal transformation that renders the bulk of material
immediately under the diamond slider conducting
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