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Measurement of shock-induced luminescence in silicon

University of British Columbia

Shock induced luminescence in silicon was measured with a time resolution of 20 ps. Polished silicon wafers were irradiated with 0.53μm laser light in a pulse of 2.7 ns FWHM at intensities ranging from 2 x 10¹⁷W/m² to 5 x 10¹⁷W/m². This produced a strong shock in the solid. The shock speeds were determined by measuring the shock transit times through targets of different thickness (68μm and 82 μm). The corresponding shock pressure was found to range from 3 Mbar to 6 Mbar. Shock induced luminescence at wavelengths of 430nm and 570nm were recorded using a streak camera which was calibrated for ablsolute response. Substantial disagreement was observed between the luminosity data and the theoretical prediction which assumes thermal equilibrium between electrons and ions in the shock wave. An electron-phonon thermal relaxation model was proposed which treated the processes of both equilibration and thermal diffusion in an electron temperature gradient behind the shock front. Calculations including such a gradient yielded good agreements with data. The electron-phonon coupling constant g in shock-compressed Si was estimated to be 10¹⁷Wmˉ³Kˉ¹ in the pressure range of interest.

Text

2010-11-05

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http://hdl.handle.net/2429/29825

Physics

University of British Columbia

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