Ejection of Au and Si nanocrystals from Au implanted Si(1 0 0) by MeV heavy ion irradiation

Si(1 0 0) substrates implanted with 32 keV Au− ions, were irradiated with 3 MeV Au3+ ions at an angle of 60°. Transmission electron microscopy (TEM) studies on sputtered particles collected on catcher grids revealed the presence of Au and Si nanocrystals. The size distribution of collected Au nanocrystals exhibited inverse power law dependence with a decay exponent of 2. Atomic force microscopy (AFM) analysis of irradiated sample showed the presence of surface craters along with hillocks. The formation of Au and Si nanocrystals in MeV ion irradiated Au doped amorphous Si layer can be attributed to the localized melting due to thermal spike phase of atomic displacement cascades produced by MeV Au ion impacts.