Thin films of size-selected Mo clusters: growth modes and structures

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Controlled synthesis of nanostructured materials is crucial for advanced applications.
• Understanding cluster-matter interactions is key to designing novel thin films.

Purpose of the Study:

• To investigate the influence of cluster size and air exposure on the growth of MoO3 thin films.
• To explore the potential of cluster deposition for creating unique nanostructured surfaces.

Main Methods:

• Deposition of size-selected, ligand-free Mo clusters under high vacuum.
• Subsequent exposure to air.
• In situ scanning tunneling microscopy (STM) for real-time observation.

Main Results:

• Growth patterns varied significantly with Mo cluster size (Mo51, Mo251, Mo1253, Mo3349).
• Small clusters formed fused monolayers, while medium clusters formed ordered monolayers.
• Air exposure induced the formation of 3D nanostructures (pylons) from aggregated clusters.
• Largest clusters showed random distribution due to zero mobility.

Conclusions:

• Cluster size and post-deposition environment critically control MoO3 thin film morphology.
• Cluster deposition offers a versatile route to engineer nanostructured surfaces and thin films.
• The formation of 3D pylons upon air exposure highlights a pathway for creating complex nanomaterials.