Experimental study and MD simulation of damage formation in GaN under atomic and molecular ion irradiation

• Damage formation in GaN under P and Ag monatomic and PF4 molecular ions was studied.
• Experiments: Molecules form thicker surface amorphous layers than monatomic ions.
• Experiments: Heavy Ag ions are more effective in bulk damage formation.
• MD simulations: Dense collision cascades form larger defect clusters.
• Large defect cluster formation intensify ion-beam damage creation.

Structure damage formation in GaN under light P and heavy Ag monatomic and small molecular PF4 ions is studied by RBS/C and classical molecular dynamics (MD) simulations. Molecules are found to be most efficient in surface amorphization, whereas in the sample bulk Ag ions produce more damage than others. Cumulative MD simulations reveal nonlinear increase of big defect cluster generation in dense collision cascades formed by molecules at the surface vicinity and along most part of Ag ion path. Creation of these big defect clusters intensifies all processes responsible for stable damage formation, in particular, it is one of the reasons of experimentally observed peculiarities of damage production.