A layer of substantially uniform lead monoxide is vapor deposited on a supported signal electrode of a vidicon target. The lead monoxide layer is formed on the signal electrode as a substantially homogeneous compensated intrinsic, or n type, electrically conductive material. An electrical potential is applied to the supported layer of lead monoxide to affect an electrical discharge through a continually renewed atmosphere consisting essentially of one of the inert gases, or nitrogen, whereby ion bombardment of the layer is accomplished.