Abstract
Controlled oxidation processes conducted on surfaces of zone refined zinc single crystals under a beam of different gases (pure oxygen, air, inert gases such as helium or argon, in the presence of small amounts of oxygen) have been studied with an electron emission microscope. Surface phenomena which take place under ionic bombardment appear to be the result of two competitive mechanisms, an activating one (introduction of defects into the surfacial layers) and a de-activating one, which can be observed expecially with inert gases (inclusion of gas atoms in the lattice). It has been ascertained that oxide nucleation is preceded by formation of an absorbed oxygen layer.
