Porous silicon layers emitting red photoluminescence (PL) have been prepared by the anodisation of p-type [100] monocrystalline Si substrate in different HF concentrations. The steady state photoconductivity of porous silicon (PS) layers as a function of electrolyte concentration, anodisation time and current density has been studied. The photoconductivity (PC) peak was observed to shift towards the shorter wavelength with the decrease in the crystallite size and it was interpreted to be the result of band gap widening. The recombination is found to have contribution from both the monomolecular and the bimolecular processes.