Fractal Crystallization Research Articles

A fractal model for the crystallization kinetics

The Kolmogorov-Johnson-Mehl-Avrami equation is wildly applied in the crystallization kinetics, and Avrami exponent involved in the equation plays an important role in crystallization process. Here we show that the Kolmogorov-Johnson-Mehl-Avrami equation can be obtained by a fractal crystallization model, and the exponent is explained as the fractal dimension in time, which depends upon the chain length and molecule weight.

Preparation Methodologies and Nano/Microstructural Evaluation of Metal/Semiconductor Thin Films

Metal/semiconductor thin films are a class of unique materials that are widespread technological applications, particularly in the field of microelectronic devices. Assessment strategies of fractal and tures are of fundamental importance in the development of nano/microdevices. This review presents the preparation methodologies and nano/microstructural evaluation of metal/semiconductor thin films including Au/Ge bilayer films and Pd-Ge alloy thin films, which show in the form of fractals and nanocrystals. Firstly, the extended version of Au/Ge thin films for the fractal crystallization of amorphous Ge and the formation of nanocrystals developed with improved micro- and nanostructured features are described in Section 2. Secondly, the nano/microstructural characteristics of Pd/Ge alloy thin films during annealing have been investigated in detail and described in Section 3. Finally, we will draw the conclusions from the present work as shown in Section 4. It is expected that the preparation methodologies developed and the knowledge of nano/microstructural evolution gained in metal/semiconductor thin films, including Au/Ge bilayer films and Pd-Ge alloy thin films, will provide an important fundamental basis underpinning further interdisciplinary research in these fields such as physics, chemistry, materials science, and nanoscience and nanotechnology, leading to promising exciting opportunities for future technological applications involving these thin films.

Probing into Interesting Effects of Fractal Ge Nanoclusters Induced by Pd Nanoparticles

Metal/semiconductor thin films are a class of unique materials that have widespread technological applications, particularly in the field of microelectronic devices. New strategies of fractal assessment for Pd/Ge bilayer films formed at various annealing temperatures are of fundamental importance in the development of micro/nanodevices. Herein, Pd/Ge bilayer films with interesting fractal nanoclusters were successfully prepared by evaporation techniques. Temperature-dependent properties of resistance and fractal dimensions in Pd/Ge bilayer films with self-similar Ge fractal nanoclusters were investigated in detail. Experimental results indicated that the fractal crystallization behavior and film resistance in Pd/Ge bilayer films are influenced significantly by annealing temperatures and fractal dimensions. The measurements of film resistance confirmed that there is an evident relationship between the film resistance and the fractal dimension. These phenomena were reasonably explained by the random tunneling junction network mechanism.

Experimental observation and simulation of fractal patterns of Au/Ge bilayer films

In this paper, we report on the simulation of fractal clusters and the comparison with experimental fractal patterns. We found that multiple fractal clusters can be formed in Au/Ge bilayer films for different annealing times. The fractal crystallization area increases with the increase in the annealing time. The random successive nucleation model can simulate the actual growth processes of multiple growth sites. The simulating fractal clusters are in good agreement with our experimental fractal patterns.

In Situ Plane-View and Cross-Sectional Transmission ElectronMicroscopy of Fractal Formation in Au/a-Ge Bilayer Films

Fractal crystallization in Au/a-Ge bilayer films has been studied by in situplane-view and cross-sectional transmission electron microscopy. Theexperimental evidence suggests that the fractal crystallization iscontrolled by both diffusion and reaction processes. The growth kineticsanalysis indicates that both diffusion-limited aggregation and randomsuccessive nucleation mechanisms play an important role in fractalcrystallization in Au/a-Ge bilayer films.

EXPERIMENTAL DEMONSTRATION OF FRACTAL SHAPE TRANSITION AND FRACTAL SIZE IN Ge CLUSTERS FORMATION

The nucleation and growth of Ge fractal clusters in Au/Ge bilayer films have been investigated by transmission electron microscope (TEM). It is found that the fractal crystallization, the fractal shape transition, and the fractal size strongly depend on the annealing time and the films thickness ratio. The fractal formation can be explained by a random successive nucleation and growth (RSNG) model. The fractal shape transition and fractal size may be determined by the relative ration between the propagation rate of RSN process and the grain growth rate.

Fractal crystallization and nonlinear V–I behavior of Au/Ge bilayer film

The fractal formation and V–I behavior of the Au/Ge bilayer film have been investigated with a transmission electron microscope and by the two-probe configuration method. The experimental results suggest that the Au/Ge bilayer film, after the fractal crystallization, shows a nonlinear V–I behavior. This phenomenon was explained by the random tunneling junction model.

In situTEM study of fractal formation in amorphous Ge/Au bilayer films

The kinetic behavior of fractal crystallization in amorphous semiconductor/metal bilayer films has been studied by in situ transmission electron microscopy. The fractal growth process exhibits three stages: rapid growth, steady growth, and slow growth. During the initial rapid growth stage, the fractal crystallization is controlled by both diffusion and reaction processes. With increasing annealing time, fractal growth is obstructed and becomes slower because more and more other fractal patterns approach from the neighborhood. The growth kinetics analysis indicates that both diffusion-limited aggregation and random successive nucleation mechanisms play an important role in fractal crystallization in the amorphous Ge/Au films.

Effect of fractal crystallization on the depositing sequence of a Pd/Ge thin film system

The behavior of fractal crystallization in a Pd/Ge thin film system of various ratios of thickness (or composition) after annealing has been investigated by transmission electron microscope. It is difficult for coevaporated Pd–Ge films to obtain fractal crystallization. The fractal structure in Pd/a-Ge bilayer films can form more easily than in a-Ge/Pd bilayer films. The fractal crystallization was restricted because of the formation of the compounds (Pd2Ge and PdGe) in the Pd/Ge thin film system. Growth of the fractal structure depends on the competition between the two processes of amorphous germanium (a-Ge) crystallization and compound formation. Fractal formation can be explained by a random successive nucleation model.

Fractal formation and tunnelling effects on the conductivity of Au/a-Ge bilayer films

The fractal crystallization of the Au/a-Ge bilayer films has been investigated, and the resistance characteristics have been first measured by the two-probe configuration method. The experimental results suggest that the resistance R of various annealing films are influenced by the fractal formation and the fractal dimension. These phenomena were explained by the Random Tunnelling Junction Network (RTJN) model.

Fractal crystallization of bile components and its role in the formation of gallstones

Fractal crystallization of bile components and its role in the formation of gallstones

BEHAVIOUR OF THE FRACTAL CRYSTALLIZATION IN Pd, Ge THIN FILM SYSTEM

The behaviour of the fractal crystallization in Pd, Ge thin film system of various ratios of thickness (or composition) after annealing have been investigated by transmission electron microscopy (TEM). It was difficult for the coevaporated Pd-Ge films to realize the fractal crystallization. The production of the fractal structure in Pd/a-Ge bilayers was easier than that in a-Ge/Pd bilayers. The fractal crystallizations were restrainted because of the formation of the compounds (Pd2Ge and PdGe) in Pd, Ge bilayers. The growting of the fractal struc ture depends on the competition of the two precesses of a-Ge crystallization and compound formation.

Experimental Analysis of the Scaling Properties of Solid Polymer Electrolytes upon Five Years of Storage: From Fractal Crystallization to Carrier Relaxation

The performances of solid‐state ambient‐temperature batteries over long time periods are found to depend strongly on the crystallization processes of the electrolytes. Some advanced materials displaying stable electrochemical properties were prepared and studied by ac measurements in an attempt to obtain a more precise knowledge of the influence of the crystallization processes of nonhomogeneous media upon the ionic conductivity. The impedance spectra have been fully described and the physical origin of each parameter is emphasized. The results are discussed in terms of an irreversible transfer of the ionic carriers across “bulk interfaces,” which may be defined as the storage location of the space charges, or more precisely as the geometrical support of any energetic singularity with respect to any intensive thermodynamic parameter. The bulk dynamic behavior of the ionic carriers in such a heterogeneous medium is described by using the fractal geometry concept. The dispersive index α is shown to be related to the fractal dimension of the media and is suggested to be connected to its crystallization state. Furthermore, some correlations between the different relaxation processes were described. The aging is found not to alter the intrinsic mobility of the ionic carriers in the amorphous phase and may be considered as a dimensional transition of the geometrical metric of the dissipative domains in the medium, and not only a simple percolation network evolution.

Fractal patterns in the annealed sandwich Au/aGe/Au

Abstract In this study, we observe the fractal crystallization in the sandwich Au/aGe/Au by use of TEM. The results indicate that the variation of annealing temperature gives rise to different morpollogy of fractals of polycrystalline Ge, whose growths may be controlled by the interplay of diffusion and nucleation. It is also found that the long range field of stress has an impact on the growth of the fractals.

Fractal crystallization in a-Ge/Au/a-Ge sandwich after annealing

Fractal crystallization in sandwiches of a-Ge/Au/a-Ge is studied. We find fractal patterns of polycrystalline Ge when annealing temperature is lower than 300°C. Their morphology and fractal dimensions vary with annealing, and experimental analyses indicate that fractal crystallization maybe results from interdiffusion and agglomeration of polycrystalline Au film.