A photoconductive device including a conductive substrate, a photoconductive layer of amorphous silicon containing at least hydrogen and a surface protection layer applied on the photoconductive layer a dopant is added in the photoconductive layer at least near the interface with the surface protection layer, and the concentration of the dopant increases in the direction perpendicular to the interface. The surface protection layer has an optical energy gap larger than that of the photoconductive layer.A further photoconductive device comprising a conductive substrate; a photoconductive layer of amorphous silicon applied on the conductive substrate and a surface protection layer of amorphous silicon applied on said photoconductive layer wherein the surface protection layer contains oxygen, and is doped with a IIIb element.