The experimental evidence of the effect of femtosecond laser pulses on the spectral response of a Silicon photovoltaic cell is demonstrated and investigated. The response of this device is covering the visible to near infrared spectral region. The responsivity of the photovoltaic cell is enhanced from 0.18A/W (0.5A/W to 0.85 A/W) to 0.25A/W, this means that the conversion efficiency increases from about 9% to about 14% due to irradiation effect. All treatments and measurements have been done at room temperature. The observed enhancement is related to the appearing of nano-structured groves in the 700-900 nm range.