Abstract: A first layer of semiconductor device is of doped amorphous silicon prepared by a glow discharge in a mixture of silane and a doping gas. The first layer is on a substrate having good electrical properties. On the first layer and spaced from the substrate is a second layer of amorphous silicon prepared by a glow discharge in silane. On the second layer opposite the first layer is a metallic film forming a surface barrier junction therebetween, i.e. a Schottky barrier. The first layer is doped so as to make an ohmic contact with the substrate. Preferably the doping concentration of the first layer is graded so the dopant concentration is maximum at the interface of the first layer and the substrate. In a second embodiment of the Schottky barrier semiconductor device an intermediate layer is between and contiguous to both the first layer and the substrate. The intermediate layer facilitates in making ohmic contact between the amorphous silicon and the substrate.