Surface-roughness–induced electric-field enhancement and triboluminescence

¹ Department of Material Science and Engineering, Massachusetts Institute of Technology - Cambridge, MA 02139, USA
² IFF, FZ-Jülich - 52425 Jülich, Germany, EU
³ Division of Nanotechnology and New Functional Material Science, Graduate School of Science and Engineering, University of Toyama - Toyama, Japan

^a b.persson@fz-juelich.de

Received: 10 July 2010
Accepted: 9 August 2010

Abstract

The separation of solids in adhesive contact, or the fracture of solid bodies, often results in the emission of high-energy photons, e.g., visible light and X-rays. This is believed to be related to charge separation. We propose that the emission of high-energy photons involves surface roughness and surface diffusion of ions or electrons, resulting in the concentration of charge at the tips of high asperities, and to electric-field enhancement, which facilitate the discharging process which result in the high-energy photons. If the surface diffusion is too fast, or the separation of the solid surfaces too slow, discharging starts at small interfacial separation resulting in low-energy photons.