Shrinkage of nanocavities in silicon during electron beam irradiation

Abstract

An internal shrinkage of nanocavity in silicon was in situ observed under irradiation of energetic electron on electron transmission microscopy. Because there is no addition of any external materials to cavity site, a predicted nanosize effect on the shrinkage was observed. At the same time, because there is no ion cascade effect as encountered in the previous ion irradiation-induced nanocavity shrinkage experiment, the electron irradiation-induced instability of nanocavity also provides a further more convincing evidence to demonstrate the predicted irradiation-induced athermal activation effect.

Atom Diffusion and Evaporation of Free-Ended Amorphous SiOx Nanowires: Nanocurvature Effect and Beam-Induced Athermal Activation Effect

“…This is because the existing theories such as the knock-on mechanism were at the first place built on consideration of the nature of equilibrium, symmetry, periodicity, and linearity of bulk crystalline structure or its approximation, whereas the beam (including electron, ion, and photon beams)-induced nanophenomena are intrinsically of non-equilibrium, amorphous, and non-linear nature. The previous research [5,[9][10][11][12] has demonstrated that our proposed nanocurvature or nanosize effect [5,13] and energetic beam-induced athermal activation or nanotime (soft mode and instability of atomic vibration) effect [5,6] could well explain the above beam-induced nanophenomena and widespreadly control the beam-induced structure changes and nanoprocessing of LDNs. Thus, it has been further asserted that both nanocurvature effect and beam-induced athermal activation effect would control as well dynamic behaviors of atom diffusion and evaporation of one-dimensional (1D) nanowire during uniform e-beam irradiation.…”

“…On the other hand, people normally resort to the existing knock-on mechanism [8] to explain or predict the energetic (ion or electron) beam-induced nanophenomena including beam-induced dynamic atomic defect creation and annihilation and atom transport processes on LDNs. However, it has been demonstrated that knock-on mechanism cannot offer a full explanation for the experimentally observed beam-induced nanophenomena, especially for these such as the plastic flow or wetting of carbon nanotube [9] and amorphous SiO x nanowire [7], or the shrinking nanocavity along with its cavity-near-surface preferential amorphization [5,10,11] as observed earlier in silicon during energetic beam irradiation. This is because the existing theories such as the knock-on mechanism were at the first place built on consideration of the nature of equilibrium, symmetry, periodicity, and linearity of bulk crystalline structure or its approximation, whereas the beam (including electron, ion, and photon beams)-induced nanophenomena are intrinsically of non-equilibrium, amorphous, and non-linear nature.…”

Non uniform shrinkages of double-walled carbon nanotube as induced by electron beam irradiation

“…Actually, even more universally, along with other experiments 14,15,22,23 (also X. F. Zhu et al, manuscripts in preparation or to be submitted), the experiment herein further confirms that the general principle of nanosize effect (i.e., nanocurature effect as specified in this letter and also including low dimensionconfinement effect at nanoscale) and nanotime effect (i.e., energetic beam-induced athermal activation effect or energetic beam induced-atomic vibration instability and soft mode effect as specified in this letter) as predicted in earlier publications [16][17][18] can be extended for elucidation of nanoinstability of LDNs of different types under such irradiations as well as for elucidation of irradiation of other energetic beams such as ion or photon (i.e., laser) beam. …”

In situTEM observation of preferential amorphization in single crystal Si nanowire

“…In fact, our previous work on the energetic beam irradiation-induced structural instabilities and processing of low dimensional nanostructures (LDNs), such as nanocavities in Si [16,[28][29][30][31], carbon nanotubes [32,33] and amorphous SiOx nanowires [22,34], has proven that our proposed nanocurvature effect [16,17] and energetic beam-induced athermal activation effect [16,18] For the nanocurvature effect on a nanowire, we can suppose that, similar to the particle case [16,17], when the diameter of a nanowire reduces down to nanoscale and can be comparable to its atomic bond length, a positive nanocurvature on the highly curved wire surface will become appreciable, as shown in Fig. 3(a).…”