Abstract: Disclosed is a method of forming finely divided photosensitive trigonal selenium particles which are submicron in size and generally spherical in shape. The method comprises forming an alkaline solution containing selenide and/or polyselenide ions, followed by the precipitation of finely divided trigonal selenium particles from said solution by the addition of an oxidizing agent to said alkaline solution. The trigonal selenium particles are formed into a binder layer photosensitive device by dispersing them with an organic resin in solution with an organic solvent which when applied to a substrate in a uniform layer, is heated to remove the solvent and form the device. Continued heat treatment of the device can result in enhancement of its ability to accept an electrostatic charge.

Abstract: Disclosed is a method for improving the photo-induced discharge characteristics of certain cadmium chalcogenides selected from the group of CdS, CdTe, CdAs, CdSe and CdSSe. The method involves calcining a mixture of the cadmium chalcogenide or a precurser thereof in the presence of cadmium oxide or a compound which decomposes upon heating to cadmium oxide in an amount sufficient to provide an excess of unreacted cadmium oxide after calcination.