Abstract: In a photovoltaic cell which comprises: a substrate, a bottom electrode, a first layer of cadmium sulfide, a second layer of cuprous sulfide forming a barrier junction with said first layer and a top electrode, the improvement wherein said substrate is an insulative ceramic material and the bottom electrode is a conductive ceramic layer fused to said substrate. Said conductive layer is optionally coated with a metal having a high electrical conductivity.

Abstract: A welded seam between overlapped edges of sheet material wherein the sheet material is heated to a temperature below the melting temperature and is forced together under high pressures to form a forged weld. The thickness of the sheet material in the weld area is reduced from double thickness to a thickness approaching a single thickness, with the weld interface being diagonally disposed. The weld is effected by grain growth across the interface such that the particular line along which the meeting surfaces of the metal are welded together is unobservable upon etching a cross section thereof and with magnification on the order of 100X. The heating is effected by applying to opposing edge portions which are to be overlapped and welded a high frequency current which effectively reduces heating to edge portions only of the metal with the heat effected area being in the vicinity of 0.1 inch.

Abstract: In a photovoltaic cell which comprises: a substrate, a bottom electrode, a first layer of cadmium sulfide, a second layer of cuprous sulfide forming a barrier junction with said first layer and a top electrode, the improvement wherein said substrate is an insulative ceramic material and the bottom electrode is a conductive ceramic layer fused to said substrate. Said conductive layer is optionally coated with a metal having a high electrical conductivity.