Midinfrared picosecond spectroscopy studies of Auger recombination in InSb

A midinfrared picosecond spectrometer based on an ${\mathrm{Er}}^{3+}$ laser-pumped optical parametric generator has been used to study Auger recombination processes in intrinsic InSb at room temperature. After carrier excitation by a 100-psec λ=2.8 μm ${\mathrm{Er}}^{3+}$ laser pulse the sample transmission change due to excess carriers was probed, using short pulses of wavelengths varying in the range 4–6 μm, as a function of time delay. It was shown that over the measured range of carrier densities (n=${10}^{16}$–${10}^{18}$ ${\mathrm{cm}}^{\mathrm{-}3}$) the momentum-conserving conduction–heavy-hole–heavy-hole–light-hole Auger process was the predominant channel for electron-hole recombination with a quadratic rather than a cubic dependence of recombination rate on carrier density. The effective Auger lifetime scales as ${\mathrm{\tau }}_{\mathrm{Aug}}^{1\mathrm{-}}$=${\mathit{C}}_2$n with ${\mathit{C}}_2$=7.4(±1.5)×${10}^{\mathrm{-}9}$ ${\mathrm{cm}}^3$ ${\mathrm{s}}^{\mathrm{-}1}$. This type of carrier concentration dependence is in accordance with theoretical predictions for semiconductors in which the electron component of the carrier population is degenerate.