Fig. 3: Effect of the hole’s localization near the surface.
a A sketch for a SiO2/N-type-Si surface under illumination. Upon illumination electrons (Δn) and holes (Δp) are generated across the bandgap, with the latter being localized near the surface. The light induces a SPV effect (dashed lines) that will flatten the bands under high injection conditions. b Real photoconductivity at RT at different fluences as indicated. c Amplitude for the real part of photoconductivity from OPTP data as function of fluence at two different pump-probe delays of 10 ps (filled symbols) and 930 ps (open symbols). Lines show the linear tendency at early (solid line) and late pump probe delays (dashed line); the relative amplitudes for both at any fluence above ~1.35 μJ cm-2 reveal the contribution of electrons (Δ\({\sigma }_{e}\)) and holes (Δ\({\sigma }_{h}\)) to the monitored photoconductivity. d Transient OPTP photoconductivity showing a correlation between the rise at 300 K and the decay in dynamics at 4 K. Horizontal line refers the initial 0.7 amplitude when compared with the one at the plateau.
