Effects of Water Vapour on the Electrical Properties of Anodized Aluminium

Abstract

IN connexion with experiments on semiconductors, one of us¹ noted the very considerable change of capacity which took place when a condenser containing aluminium oxide as the dielectric material was placed in a system which was then evacuated. The change of capacity was ascribed to the removal of adsorbed water from the porous aluminium oxide. In the above investigation, the condenser consisted of an aluminium sheet, of an aluminium oxide layer formed electrolytically (by ‘anodizing’) on the sheet, and of a thin metallic layer of aluminium evaporated on to the oxide film. The aluminium sheet and the evaporated surface then formed the plates of the condenser.