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DS: Dünne Schichten

DS 8: Ionen-Festkörper-Wechselwirkung I

DS 8.4: Vortrag

Samstag, 5. März 2005, 16:00–16:15, TU HS107

Effect of ion irradiation on Au nanoparticles deposited onto Si substrates — •Andreas Klimmer¹, Masaki Ozawa², Anitha Ethirajan¹, Hans-Gerd Boyen¹ und Paul Ziemann¹ — ¹Abt. Festkörperphysik, Universität Ulm — ²Zentrale Einheit Elektronenmikroskopie, Universität Ulm

Arrays of hexagonally arranged Au nanoparticles on top of Si substrates (∅ ≈ 10 nm, interparticle distances ≈ 80 nm) were sequentially irradiated with 200 keV Ar⁺ ions up to fluences of 10¹⁶ ions/cm². The bombarded structures were analyzed by high-resolution SEM, AFM as well as cross-sectional TEM.

The Au nanoparticles seem to be stable up to a fluence of ∼ 10¹⁵ ions/cm² (∼ 800 ion impacts on one nanoisland). Upon further irradiation the average particle height relative to the substrate level diminishes according to SEM and AFM. Subsequently, these techniques suggest an almost complete disappearance of the particles at fluences above 10¹⁶ ions/cm².

However, TEM measurements reveal that the Au particles have not been just sputtered from the surface but complete particles can be re-detected within the Si substrate with their spherical shape conserved. This surprising effect might be due to bombardment induced changes in the visco-elastic properties of the underlying Si substrate. Whether for that process the substrate close to the nanoparticle has to be amorphized by the ion beam is not clear, yet.