Figure 3: Relaxation time customization by element doping.

(a) Time-resolved ΔT/T₀ traces at a probe wavelength of 6.0 μm for the Cd₃As₂ samples with different Cr concentrations, showing faster photocarrier relaxation times for higher Cr concentrations. (b) The fitted recovery time constants as a function of Cr concentration at probe wavelengths of 3.0, 4.5 and 6.0 μm. The data points obtained from the same sample are connected by dashed lines to guide the eye. (c) Linear relationship between the inverse relaxation time τ⁻¹ and the square of the doping concentration n². The lines (linear fitting) reveal that the scattering rate agrees with the equation , where Δ is the doping-induced band gap and and D are constants that are independent of the band gap.