AlOx

AlOx refers to aluminum oxide compounds with variable oxygen content. In most contexts it denotes aluminum oxide (Al2O3), the stable oxide of aluminum, but the term is also used for substoichiometric or amorphous oxides in thin films, where the oxygen-to-aluminum ratio deviates from 3.

Aluminum oxide exists in several phases. The most common crystalline phase is alpha-Al2O3 (corundum), known for high hardness and thermal stability. Amorphous and substoichiometric AlOx films are insulating materials with wide band gaps and can exhibit tunable electrical properties through oxygen vacancies and variations in stoichiometry.

Synthesis and processing methods include oxidation of aluminum metal, anodization, thermal oxidation, and various chemical approaches such as chemical vapor deposition, atomic layer deposition, sputtering, and sol-gel processing. The chosen method influences crystallinity, density, and oxygen content, enabling a range of material properties from dense ceramics to insulating thin films.

Applications are diverse. Aluminum oxide is widely used as a ceramic abrasive (alumina), a protective coating, and a dielectric layer in microelectronics. It also serves as a UV-transparent optical material (in sapphire form) and as a catalyst support (gamma-alumina). Substoichiometric AlOx films are investigated for resistive-switching devices and other oxide-based electronics, where controlled oxygen content can tailor switching behavior.

Safety and handling: Solid aluminum oxide is chemically inert and of low toxicity, but inhalation of dust can pose health risks; appropriate handling and PPE are advised in industrial settings.