Atomic Layer Deposition

atomic layer deposition (ALD), is a thin-film growth technique that offers the unique capability to coat complex, three-dimensional objects with precisely fitted layers.

The three images illustrate how a combination of anodized aluminum oxide (AAO) and atomic layer deposition (ALD) provides precisely controlled, ultra-uniform porous support for new and well-defined catalysts. Credit: ANL

The scientists expose an object to a sequence of reactive gas pulses to apply a film coating over the object’s surface. The chemical reactions between the gases and the surface naturally terminate after the completion of a “monolayer” exactly one molecule thick. ALD can deposit a variety of materials, including oxides, nitrides, sulfides and metals.

Potential applications are more efficient and less costly solar cells, solid-state lighting and industrial catalysts, improved superconductors and separation membranes.