The role of intercarrier scattering in excited silicon

Abstract

We have used laser and electron-beam excitation to investigate the influence of intercarrier scattering upon several properties of high-purity silicon, viz. the drift and Hall mobilities, the ambiopolar diffusion coefficient, the optical absorption cross section (at 10.6 μm) and Verdet coefficient (at 1.06 μm), covering the carrier density range n = 1015 − 4 · 1018 cm−3. The mobility data obtained are in accordance with theoretical models that take both lattice scattering and electron-hole (e-h) scattering into account as the main scattering mechanisms. In the region above n ≈ 1017 cm−3 the additional effects of electron-electron and hole-hole scattering must be considered as well. For the other parameters studied, however, lattice scattering alone is found to be quite dominant. Finally, the Caughey-Thomas formula for the mobilities in doped silicon has been modified to be applicable to the present case of a light-induced e-h plasma.