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Fracto‐mechanoluminescence induced by impulsive deformation of II–VI semiconductors
Author(s) -
Tiwari Ratnesh,
Dubey Vikas,
Ramrakhiani Meera,
Chandra B. P.
Publication year - 2015
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.2837
Subject(s) - mechanoluminescence , intensity (physics) , luminescence , semiconductor , electron , photoluminescence , saturation (graph theory) , materials science , atomic physics , light intensity , condensed matter physics , chemistry , optics , optoelectronics , physics , mathematics , quantum mechanics , combinatorics
When II–VI semiconductors are fractured, initially the mechanoluminescence (ML) intensity increases with time, attains a maximum value I m at a time t m , at which the fracture is completed. After t m , the ML intensity decreases with time, I m increase linearly with the impact velocity v 0 and I T initially increase linearly with v 0 and then it attains a saturation value for a higher value of v 0 . For photoluminescence, the temperature dependence comes mainly from luminescence efficiency, η o ; however, for the ML excitation, there is an additional factor, r t dependent on temperature. During fracture, charged dislocations moving near the tip of moving cracks produce intense electric field, causes band bending. Consequently, tunneling of electrons from filled electron traps to the conduction band takes place, whereby the radiative electron–hole recombination give rise to the luminescence. In the proposed mechanism, expressions are derived for the rise, the time t m corresponding to the ML intensity versus time curve, the ML intensity I m corresponding to the peak of ML intensity versus time curve, the total fracto‐mechanoluminescence (FML) intensity I T , and fast and slow decay of FML intensity of II–VI semiconductors. The FML plays a significant role in understanding the processes involved in biological detection, earthquake lights and mine failure. Copyright © 2015 John Wiley & Sons, Ltd.