The photovoltaic (PV) properties of undoped amorphous silicon (a-Si)/ p-type crystalline silicon (c-Si) solar cells were found to improve by a hydrofluoric acid treatment of c-Si just prior to glow discharge deposition of a-Si. The short circuit current density (Jsc) improved from 2.7 to 23.5 mA/cm2 for an 0.1 μm thick a-Si layer. This also resulted in an improved spectral response of the solar cell in the violet region of the spectrum. The enhanced properties have been attributed to the improved carrier transport across the interface, as seen in the current-voltage-temperature relationships, and also PC-1D simulation of the devices. Solar cells of a similar type were also fabricated by dc magnetron sputtering of the a-Si layer. HF passivated cells (area ∼ 0.24 cm2) yielded about 9.5 % efficiency with Jsc of 30 mA/cm2 and a FF of 0.6, without use of an A/R coating. The variation of the PV properties of these cells was investigated as a function of a-Si thickness and c-Si doping.