Amorphous silicon (a-Si:H) solar cells based on p.i. n junctions have been produced by a Two Consecutive Decomposition and Deposition Chamber (TCDDC) system , either using Wide Band Gap-μc (WBG-μc) films or normal doped ones, as contact layers. The role of such doped layers on device's performance (open circuit voltage, Voc, short circuit current density, Jsc, fill factor, FF, and conversion efficiency, η) have been determined by spectral response and I-V curve measurements. The obtained data show that Voc is enhanced over more than 25% by using WBG-μc films with thicknesses bellow 300 Å as doped contacts, when compared with normal p.i.n junctions . Besides this, if a smooth grade interlayer, based on a-Si:C doped alloys, is added between junctions , Voc higher than 1.0 V with η ≥7.5% are obtained in single structures.