Amorphous silicon alloyed p-i-n solar cells have been fabricated using a separate chamber photochemical vapor deposition system. The photocharacteristics of such cells have been modestly improved by the addition of a carbon-alloyed graded-band-gap layer at the p(a-SiC:H)/i(a-Si:H) heterointerface. The best efficiency obtained for a glass/TCO (transparent conductive oxide)/p(a-SiC:H)/i(a-Si:H)/n(μc-Si:H)/metal structure of this type was 11.2% for a 3×3 mm2 cell; other parameters were Voc=0.882 V, Isc=18.05 mA/cm2, and a fill factor (FF) of 0.702.