Atomic layer growth on Al(111) by ion bombardment

Area of Science:

• Materials Science
• Surface Science
• Ion-Solid Interactions

Background:

• Ion bombardment typically causes surface erosion via crater formation.
• Understanding surface morphology changes under ion irradiation is crucial for materials processing and device fabrication.

Purpose of the Study:

• To investigate the surface morphology evolution of Al(111) under rare gas ion bombardment.
• To elucidate the underlying mechanism responsible for unexpected surface modifications.

Main Methods:

• Al(111) surface was subjected to bombardment with Ne+, Ar+, and Xe+ ions.
• Experiments were conducted at various temperatures and ion energies (down to a few hundred eV).
• Surface morphology changes were analyzed to determine the nature of the modification.

Main Results:

• Contrary to expectations, initial surface growth of several atomic layers was observed instead of cratering.
• This surface growth phenomenon occurred for all tested rare gas ions (Ne+, Ar+, Ar+, Xe+).
• The effect was observed across a range of temperatures and ion energies.

Conclusions:

• The observed surface growth is attributed to a thermal spike-induced mechanism.
• This mechanism leads to the separation of irradiation-induced damage into subsurface vacancy clusters and surface adatom clusters.
• The findings challenge conventional models of ion-induced sputtering and suggest new possibilities for surface modification.