“…As both the`light-on' and the`light-off' transients are non-exponential, Lagowski et al concentrated instead on the measured slopes of the SPV curve, obtained immediately after switching the light on and off (see Fig. 79 [110,362], GaAs [319], ZnO [401], CdSe [377] and CdTe [749] surfaces. Moreover, if the SPV transients are analyzed at many different wavelengths, the dependence of the optical cross-section on the photon energy can be constructed [378,623].…”