Lightly doped hydrogenated amorphous silicon thin films were deposited through the plasma enhanced chemical vapor deposition(PECVD) technique using a gas mixture of Si H4, B2H6,and H2 as the precursor. By using thermal annealing at 800 and 1000°C, boron doped nanocrystalline silicon films were obtained. X-ray photoelectron spectroscopy(XPS) measurements demonstrated the presence of substitutional boron in the doped films. Based on the measurement of dark conductivity as a function of temperature, p-type nanocrystalline silicon(ncSi:H) films with high room temperature conductivity and low active energy were observed. By using these p-type silicon films,P-N junction solar cells were prepared on the n-type nc-Si substrate. The device characteristics were investigated based on the measurements of the current-voltage and spectral-response.