Effect of titanium ion implantation and the gas atmosphere on the electrophysical properties of alumina

The energy and kinetic characteristics of the dark conductivity and photoconductivity of polycrystalline alumina irradiated by titanium ions and then annealed in vacuum and air have been studied. The effect of temperature on the properties and electron-transport mechanisms is determined. In the air pressure range from 105 to 1 Pa, the electrophysical properties are reversible. A semiconductor coating can be formed on the alumina surface via vacuum annealing; when heated in air, it becomes insulating. The reverse transition is also possible. These modifications are related to the formation of defects, accumulation of oxygen-containing complexes, and changes in the stoichiometric compositions of the compounds synthesized by the ion thermal treatment.