Band structure of In0.53Ga0.47As, taken from Ref. 17 . The red arrows represent photoexcitation at 1400 nm, the blue arrows at 800 nm; the dotted line marks the energy of the L-valley minimum.
Depth profile of calculated (SRIM) and measured (SIMS) Br-ion implantation densities.
Scheme of the experimental setup in non-collinear for time-resolved THz spectroscopy. D1—motorized stage for controlling the pump-probe delay (τ p ), TOPAS—optical parametric amplifier, E—emitter (ZnTe crystal), M—ellipsoidal mirrors, D2—motorized stage for scanning the THz pulse profile, L—pellicle beam-splitter, S—sensor (ZnTe crystal).
Complex transient conductivity spectra: experimental data (symbols) and the Drude fit (lines) for sample A (left) and sample C (right).
Transient conductivity spectra of the sample D in the two-dimensional frequency domain (in Ω−1 THz−1 m−1). (a) real part measured and (b) fitted, respectively; (c) and (d) imaginary part measured and fitted, respectively; (e) and (f) amplitude of the complex conductivity measured and fitted, respectively; and (g) residuals of a complex fit. The complex fitting was done by using Eq. (2) which assumes an exponential decay of the free carrier concentration with the lifetime τc.
Decay of the normalized ultrafast conductivity for samples A, B, and C and for several initial photocarrier densities. We plot the evolution of the photoconductivity at 1 THz [i.e., Δσ(ω0 = 2π × 1012s−1,τp)] obtained following the method described at the end of the Sec. III . Note that the vertical scale for plots (b)–(d) is logarithmic. Experiment: symbols, fit: lines.
Comparison of (a) carrier lifetimes [τc is effective carrier lifetime obtained in experiments with photoexcitation at 800 nm, 15 τe is the lifetime of electrons, and τh is the lifetime of holes] and (b) mobilities [µc refers to Ref. 15 , µe is the mobility of electrons, and µh is the mobility of holes] as a function of host-atom displacement concentration. Closed symbols: excitation at 800 nm; 15 open symbols: excitation at 1400 nm.
Sheet resistivity ρsheet and Hall mobility µHall obtained by DC resistivity and Hall measurements (∼10% experimental error); scattering time τs,e and mobility µe obtained by fitting the transient conductivity spectra with the Drude formula Eq. (1) for the specified range of initial carrier concentrations n 0 (values obtained from the fit).
Summary of the values of parameters stemming from the kinetic model Eq. (4) of the decay of electron and hole populations.
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