Fig. 2: Fluence dependence of the SPV.
a Fermi-edge fits (blue) to delay scan spectra represent the chemical potential as a function of delay at multiple fluences from 0.92 to 27.5 μJ/cm2. The decay scans are fitted best by the sum of two positive amplitude exponentials and one negative exponential term (red dashed). The SPV peak (yellow dots) occur at later delays with decreasing fluence. b The build-up time of the SPV peak log-log plotted as a function of fluence. The data fits best to a 3D diffusion model. Due to discrete delay steps, fluences above 10 μJ/cm2 have peak SPV values at τ = 0 and are not plotted. c SPV magnitude versus fluence as determined by the amplitude of the long ~10 ns timescale in the three-exponential model. The teal dashed line depicts the expected trend of the SPV magnitude from the theory discussed in the text. The inset figure demonstrates the same data on a log scale of fluence. d SPV decay constant versus fluence as determined by the time constant in the long timescale in the three-exponential model. The error bars are conservative estimates determined by reapplying the fits in the worst case scenarios for variation in pump fluence added in quadrature with the respective covariance from the fits. The teal-shaded region represents two standard deviations of slope and y-intercept of the weighted best fit trend line.
