Ion implantation in nanodiamonds: size effect and energy dependence

Abstract

Nanoparticles are ubiquitous in nature and are increasingly important for technology. They are subject to bombardment by ionizing radiation in a diverse range of environments. In particular, nanodiamonds represent a variety of nanoparticles of significant fundamental and applied interest. Here we present a combined experimental and computational study of the behaviour of nanodiamonds under irradiation by xenon ions. Unexpectedly, we observed a pronounced size effect on the radiation resistance of the nanodiamonds: particles larger than 8 nm behave similarly to macroscopic diamond (i.e. characterized by high radiation resistance) whereas smaller particles can be completely destroyed by a single impact from an ion in a defined energy range. This latter observation is explained by extreme heating of the nanodiamonds by the penetrating ion. The obtained results are not limited to nanodiamonds, making them of interest for several fields, putting constraints on processes for the controlled modification of nanodiamonds, on the survival of dust in astrophysical environments, and on the behaviour of actinides released from nuclear waste into the environment.

Modification of nanodiamonds by xenon implantation: A molecular dynamics study

“…In this paper, we showed how molecular dynamics simulation can be quantatively used to study implantation of xenon into nanodiamonds (NDs). Following on from our previous study [8], we provided detail on the key experimental/simulation result, namely, that a primary knock-on atom (PKA) energy around 6 keV provides maximal damage. We also detailed a pronounced size effect, showing that small NDs (below 3-4 nm diameter) are easily destroyed, losing many atoms and graphitizing those which remain.…”

“…1(a) in Ref. [8]) that provide a heat-loss path. Based on the simulation results, it is reasonable to propose that 1 ps of annealing is about right, while 10 ps is certainly too much, particularly since each ND will have some degree of thermal contact with several other NDs.…”

Behavior of implanted Xe, Kr and Ar in nanodiamonds and thin graphene stacks: experiment and modeling

“…For the XANES measurements, a relatively high concentration of the target ion (Xe/Kr) is desirable. At the same time, nanoparticles can be strongly heated or even completely destroyed by a single ion [14][15][16] and thus sputtering of upper layers of nanograins will occur. In our experiments the fluence was between 5-8×10 15 at/cm 2 with a dose rate of ~8×10 12 at/cm 2 •sec.…”

“…According to several independent works the Xe-V defect is the most stable configuration for this impurity in diamond. 14,16,49,50 However, experimental confirmation of this model are yet lacking, since detailed investigations of Zeeman splitting and polarization dependence of photoluminescence of known Xe-related defects do not allow unambiguous selection of a defect model. 51,52 Figure 8a shows a diamond lattice with a Xe-V complex as obtained by QuantumEspresso modelling.…”

“…Interestingly, in bulk diamond only a rather small (~10%) fraction of implanted Xe ions forms stable luminescing complexes (presumably, Xe-V) and annealing to temperature of at least 800 °C is required to anneal radiation damage and drive the implant to stable lattice position. 47,48 However, the heat released in the interaction of the implanted ion with a nanodiamond grain [14][15][16] might be sufficient to induce lattice reconstruction and formation of the Xe-V. Our attempt to observe room temperature photoluminescence of Xe-related defects using 405 nm excitation was not successful, but it is possible that employed ion fluence was excessive (see dependence of the Xe-defects luminescence from ion fluence in Ref. 52) The model for isostructural Kr-V defect was constructed, the nearest C atoms are at 2.1 Å.…”