Properties and fabrication technical data on glow discharge produced hydrogenated amorphous silicon carbide have been described. A series of experimantal studies of the tffects of impurity doping on the amorphous silicon carbide has also been carried out. It has been shown from the experiment that a hydrogenated amorphous silicon carbide prepared by the plasma decomposition of [SiH4(i-x) +CH4(x)] gas mixture has a good valency electron controllability. Employing the property of the valency controlled a-SiC: H as a wide gap window junction, a-SiC: H/a-Si: H heterojunction solar cells have been fabricated. As a result, we have succeeded to break through an 8% efficiency barrier with this new material. A typical performance of a-SiC: H/a-Si: H heterojunction cell is Jsc of 15.21 mA/cm2, Voc of 0.88 volts, FF of 60.1% and η of 8.04%.