The phosphorus-doped amorphous carbon (n-C:P) films were grown by r.f. power-assisted plasmaenhanced chemical vapor deposition at room temperature using solid phosphorus target. The influence of phosphorus doping on material properties of n-C:P based on the results of simultaneous characterization are reported. Moreover, the solar cell properties such as series resistance, short circuit current density (J(sc)), open circuit current voltage (V-oc), fill factor (FF) and conversion efficiency (eta) along with the spectral response are reported for the fabricated carbon based n-C:P/p-Si heterojunction solar cell were measured by standard measurement technique. The cells performances have been given in the dark I-V rectifying curve and I-V working curve under illumination when exposed to AM 1.5 illumination condition (100 mW/cmz, 25 degrees C). The maximum of V, and J(sc) for the cells are observed to be approximately 236V and 7.34 mA/cmZ, respectively for the n-C:P/p-Si cell grown at lower r. f. power of 100 W. The highest eta and FF were found to be approximately 0.84% and 49%, respectively. We have observed the rectifying nature of the heterojunction structures is due to the nature of n-C:P films. (c) 2006 Published by Elsevier B.V.