Figure 1
Surface photovoltage effect.
(a1, a2) Pump-power dependence of the photovoltaic shift of the spectra recorded at T = 10 K. Spectra recorded at p = 0 and 46 µJ/cm2 are also displayed with the latter shifted in energy to overlap the former. Inset to (a2) schematically shows the pump and probe pulses arriving repetitively on the sample with the pump-probe delay of -1 ps. (b) Pump-power dependence of the photovoltaic shift at T = 10 K. (c1, c2) Temperature dependence of the photovoltaic shift. Spectra recorded with and without pump at various temperatures are displayed. Pump power was p = 29 µJ/cm2 and the pump-probe delay was set to t = -1 ps. (d) Temperature dependence of the shift induced by p = 29 µJ/cm2. Schematic of the upward surface band bending is also shown. Error bars in (b) and (d) are smaller than the marker size.
