The formation of hollow metal oxide nanoparticles through the oxidation process at low temperatures from 295 to 423 K has been studied by transmission electron microscopy for Cu, Al, and Pb. For Cu are obtained as a result vacancy aggregation in processes, resulting rapid outward diffusion ions layer during process. On other hand, Pb turn solid PbO because diffusivity difference DPb<DO does not lend itself clusters. growth behavior Al larger size summarized follows: (i) rapidly...

The self-diffusivity of oxygen in amorphous Al2O3 (a-Al2O3), a-Ta2O5, and a-Nb2O5 was investigated along with structural analysis terms pair distribution function (PDF). low activation energy, ∼1.2 eV, for diffusion the oxides suggests a single atomic jump ions mediated via vacancy-like defects. However, pre-exponential factor a-Ta2O5 lower bond energy two orders magnitude larger than that a-Al2O3 higher energy. PDF analyses revealed short-range configuration more broadly distributed...

The oxidation behaviour of Ni nanoparticles at temperatures from 573 to 673 K and the formation process hollow oxide particles were studied by transmission electron microscopy. In course oxidation, a single large void was observed one site interface between inner outer NiO layer due vacancy clustering, which occurs during resulting rapid outward diffusion ions through layer. This suggests that supersaturated vacancies generated migrate over long-range distance aggregate site. fully oxidized...

The electron-irradiation-induced crystallization of amorphous Al2O3 (a-Al2O3) was investigated by in-situ transmission electron microscopy under the wide electron-energy region 25–300 keV. formation γ-Al2O3 nanocrystallites induced irradiating a-Al2O3 thin film along with nanovoids in crystalline grains regardless acceleration voltage. became more pronounced decreasing energy, indicating that electronic excitation processes play a dominant role γ-Al2O3. Radial distribution analyses suggested...

We investigated the effect of low-flux electron irradiation with 125 keV to sputter-deposited amorphous germanium on structure and electron-induced crystallization microstructure by TEM following our previous study aging at room temperature. In samples aged for 3 days, coarse, spherical particles about 100 nm in diameter appear dominantly. By pre-irradiation samples, a reduction size number coarse particles, embedded matrix fine nanograins diamond cubic structure, was noted increase fluence....

The structure of amorphous Ge (a-Ge) films prepared by sputter-deposition and the effects aging at ambient temperature pressure were studied pair-distribution-function (PDF) analysis from electron scattering molecular dynamics simulations. PDFs as-deposited aged samples for 3–13 months showed that major peaks Ge-Ge bonds decrease in intensity broaden with up to 7 months. In a-Ge simulation obtained quenching liquid different rates, peak intensities a slowly cooled model are higher than those...

Following our previous studies on crystallization induced by electron irradiation, we have investigated the of sputter-deposited amorphous germanium films heat treatments. On continuous heating, samples aged for 3 days and 4 months at room temperature crystallized 500°C to form coarse spherical particles a hexagonal structure, about 100 nm in diameter, whereas 7 turned homogeneous nanograins diamond cubic structure 600°C. When were annealed 350°C 2 h then heated, they 550°C mixture two...

The effect of W on the nanovoid formation in annealed amorphous Al2O3 was studied by transmission electron microscopy and molecular dynamics simulations. A comparison void behavior electron-beam deposited (without W) resistance-heating (with 10 at. % revealed that enhances growth nanovoids. An analysis pair distribution function (PDF) both types showed introduction into brings about a significant change structure. Furthermore, it found high-angle annular dark-field scanning (HAADF-STEM)...

Crystallization processes of amorphous germanium–tin (GeSn) under low-energy electron-beam irradiation were examined using transmission electron microscopy (TEM). Freestanding GeSn thin films irradiated with a 100 keV beam at room temperature. The was athermally crystallized by irradiation, when the flux exceeded critical value. Heterogeneous structures consisting nano- and micro-crystallites formed after crystallization ∼24 at. % Sn in as-sputtered state. In situ TEM observations structural...

The solubility limit of tin (Sn) in germanium (Ge) is very small, and, therefore, it difficult to synthesize high Sn concentration GeSn crystals by conventional methods. An amorphous phase can contain elements beyond the crystal state, recrystallization alloy one possible ways realize materials far from equilibrium state. To suppress precipitation during thermal annealing, knowledge crystallization processes required. In present study, thin films with different concentrations were prepared...

The crystallization behavior of sputter-deposited films amorphous Si (a-Si) and SiGe alloys (a-SiGe) induced by electron irradiation at room temperature thermal annealing was investigated in situ transmission microscopy. On temperature, extremely rapid crystallization, so-called explosive occurred a higher flux but not lower flux. annealing, preferentially partially low temperatures Ge-rich a-SixGe100−x for x < 50 > 50. These results indicate that the increase content a-SiGe...

In amorphous germanium (a-Ge) and silicon films, extremely rapid crystallization, called explosive is known to occur by instantaneous processes such as mechanical stimulation, laser irradiation, electron irradiation. the present study, using transmission microscopy, we have investigated crystallization of a-Ge induced irradiation flash-lamp annealing (FLA). We found that mode depends on state: occurred both FLA in pristine while it did not those aged at room temperature for over 6 months. a...

The crystallization of sputter-deposited substrate-free films amorphous germanium was induced by electron irradiation at SEM-level energies less than 20 keV ambient temperature using an probe microanalyzer. Instantaneous crystallization, referred to as explosive occurred consistently 2–20 keV; the threshold fluxes is 1015–1016 m−2 s−1, which five six orders magnitude lower those 100 reported previously. This process expected be advantageous in production polycrystalline Ge since it rapid,...

The self-diffusion coefficient of Al in the B2-type intermetallic compound Fe-48 at.% has been determined using intrinsic diffusion coefficients Fe and with help Darken-Manning relation. is estimated to be a factor about 0.6 smaller than that Fe, activation energy for obtained 280 kJ mol−1 which little larger value 262 indicating mechanisms both components are nearly equal.