A new approach to the problem of high resolution shadow-casting: The simultaneous evaporation of platinum and carbon
Introduction. The problem of shadowing specimens for high resolution is well known. Existing shadowing materials of high atomic number, generally metals, form small aggregates or crystallites, the size of which limits the resolution obtainable. Materials of low atomic number which may not form aggregates, are unsuitable because they give insufficient contrast in the electron microscope. Many workers have attempted to reduce the amount of aggregation by varying the conditions of evaporation of the shadowing material but lack of success in these attempts, and other experimental evidence suggests that appreciable aggregation occurs under electron bombardment within the instrument. It follows, therefore, that it is the shadowing material itself which is the limiting factor rather than the conditions of deposition.