Sputtering and redeposition of ion irradiated Au nanoparticle arrays: direct comparison of simulations to experiments

Abstract

Ion beam processing of surfaces is well known to lead to sputtering, which conventionally is associated only with erosion of atoms from the material. We show here, by combination of experiments and a newly developed Monte Carlo algorithm, that in the case of nanoparticles in a regular twodimensional array on surfaces, the redeposition of sputtered atoms may play a significant role on the system development. The simulations are directly compared to in situ experiments obtained using a dual focused Ga + ion beam system and high resolution scanning electron microscopy, and explain the size evolution by a combination of sputtering and redeposition of sputtered material on neighboring particles. The effect is found to be dependent on the size of the nanoparticles: if the nanoparticle size is comparable to the ion range, the reposition is negligible. For larger nanoparticles the redeposition becomes significant and is able to compensate up to 20% of the sputtered material, effectively reducing the process of sputtering. The redeposition may even lead to significant growth: this was seen for the nanoparticles with the sizes much smaller than the ion range. Furthermore, the algorithm shows that significant redeposition is possible when the large size neighboring nanoparticles are present.

Large fraction of crystal directions leads to ion channeling

“…The issue is of increased current interest due to the use of increasingly low energies in industrial ion irradiation [17] and also the interest in examining ion modification of single nanostructures where the energies are small to maximize the irradiation effects on the nanostructure [18][19][20]. Some of these studies have shown a large variability in the radiation response of seemingly identical nanorods or nanoparticles [18,19,21], an effect difficult to explain by other means than channeling.…”

Structural and optical properties of HDPE implanted with medium fluences silver ions

“…The decrease of the band gap may be due to the increase oh the structural disorder or defects generated due to the ion implantation that formed silver nano-clusters confirmed earlier using (SEM, TEM). Furthermore, the defects are created because of several factors, but the most important are radiation damage and very high local heating through latent tracks [26][27][28][29][30]. As a final result, the optical gap decreases slightly due to the increase of disorder and silver cluster defects in the polymer matrix.…”

“…Probably, isolated electrically charged nanoclusters, when present in the polymer structure, give rise to an electric field within the bulk polymer. The internal fields thus produced strongly affect the band structure [27][28][29][30][31][32][33]. The increase of disorder and radiation damage defects in the structural polymer bonding with increasing silver ion fluences in HDPE results in decrease of optical band gap.…”

Vanishing influence of the band gap on the charge exchange of slow highly charged ions in freestanding single-layer MoS2

“…Besides conventional use of the ion's kinetic energy for tailoring material properties, an increased charge state of the ion also leads to substantial energy deposition [6][7][8][9]. Especially for low-dimensional materials, like nanowires [1], nanodots [10], and two-dimensional (2D) layers [11][12][13], ion irradiation represents a promising tool for defect engineering, which should ideally be confined to the topmost surface layer. For these classes of materials, the presence of defects can strongly affect their electronic [14], optical [15], and mechanical [16] properties.…”