We studied of the photocurrent spectra in ensembles of Si nanocrystallites (NCs) embedded in a SiO₂ matrix, above the conductivity percolation threshold of the NC phase, as functions of the average NC size and temperature.  The photocurrent spectra clearly manifest the quantum confinement effect and seem to provide reliable band-gap estimates for this high NC density (and size) regime, where the photoluminescence is already quenched due to carriers delocalization. The light soaking effect was found to be enhanced with the increase of the NCs density, suggesting that the oxide encapsulation passivates efficiently the dangling bonds on the surfaces of the NCs.  These results are consistent with our previous conclusions regarding the radiative emission and the extended states transport mechanisms in such ensembles.  This explains, and provides further insight into the significance of surface recombination even in systems where the optical absorption depth is much larger than the size of the light absorbing particles.