Luminescence induced by moving dislocations in crystals

Publisher Website
Google Scholar
Abstract
Considering the basic processes involved in mechanoluminescence (ML) excitations, a theoretical approach is made to understand the different characteristics and to evaluate different parameters of the ML induced during deformation of the crystals of X- or γ-irradiated alkali halides, II–VI compounds, and metals. It is shown that the moving dislocations produced during plastic deformation of crystalline materials cause light emission due to several processes like mechanical or electrostatic interaction of dislocations with defect centres, the dielectric breakdown of adsorbed gaseous molecules by the surface accumulated dislocation charges, the generation of holes during decay of mobile dislocations on the surface of crystals, etc. On the basis of rate equations, expressions are derived for the rise and decay of ML intensity at a given strain-rate. The estimated values of the ML intensities for different crystals are found to be comparable with the experimentally observed values. The expressions derived are able to explain the dependence of ML intensity on several parameters like strain-rate, defect centre density, temperature, applied stress, crystal-size etc. Finally, the importance of dislocation-induced ML is explored.

This publication has 39 references indexed in Scilit: