Design of Broadband Optical Interference Filters Based on Six-Layer Period

The paper proposes new approach top the design of wide-band interference filters with suppression adjacent stop-bands. The method of research of the multi-layered interference system, allowing to find the necessary of refractive indices of layers, is presented. The results described in communication open new possibilities for construction and calculation of devices based on thin film materials. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3095

Molecular dynamics simulation of amorphous SiO

Amorphous SiO2 thin films have been studied via molecular dynamics (MD) simulations. Thin film models (with two free surfaces) have been obtained by cooling from the melt with reactive force field (ReaxFF) potential. Structural and dynamic properties of the thin films are analyzed via radial pair distribution functions (RPDFs), coordination number distributions, ring statistics and bond-angle distributions. Fraction and role of structural defects have been analyzed and discussed. We also show temperature dependence of various thermodynamic quantities of the system. We found that structure of interior of thin films is close to that of the bulk while surface region contains a large amount of structural defects including dangling bonds, undercoordinated sites, small membered rings. Small and large membered rings concentrate mainly in the surface region and their fraction has a tendency to decrease with decreasing temperature

Evolution of the Graphene Layer in Hybrid Graphene/Silicon Carbide Heterostructures upon Heating

The hybrid graphene/SiC model is studied via molecular dynamics simulation to observe the evolution of the graphene layer upon heating. A two-layer model containing 10,000 graphene atoms and 7000 SiC atoms is heated from 50 K to 6000 K via Tersoff and Lennard-Jones potentials. The melting point zone is defined as the temperature range from 4400 K to 4600 K, which is close to the melting zone of graphite in an experiment. The Lindemann criterion for the 2D case is calculated and used to observe the appearance of liquid-like atoms. The evolution upon heating is analyzed on the basis of the occurrence/growth of liquid-like atoms, the radial distribution functions, and the formation of clusters. The liquid-like atoms tend to form clusters, and the largest cluster increases in size slightly to form a single largest cluster of liquid-like atoms

Melting of crystalline Si nanoparticle investigated by simulation

In the present work, we use molecular dynamics (MD) simulations to investigate melting of the crystalline Si nanoparticle. Atoms in the nanoparticle interact with each other via the Stillinger-Weber potential. Two heating rates are used. We find that melting of the nanoparticle occurs via propagation of quasi-liquid layer from the surface into the core of the nanoparticle until this layer reaches the critical thickness. We find heating rate affects on mechanism of melting of Si nanoparticle, i.e. coexistence of the two melting mechanisms (homogeneous and heterogeneous ones) occurs if low heating rate is used and it is unlike that proposed in the past. Size affects on melting of Si nanoparticle are found and discussed. In addition, we find that the global bond order parameters Ql can be used to detect melting of Si system unlike some calculations presented in the past