A hybrid modeling approach combining two-dimensional atomistic molecular dynamics simulations of vacancy formation with a continuum analysis of vacancy diffusion has been used to predict the vacancy content of vapor deposited nickel as a function of deposition rate/temperature and incident flux energy/angle. The hybrid approach uses a previously developed molecular dynamics technique to obtain ...

The e ects of impurity atoms as well as various growth methods to the formation of vacancy type defects in gallium nitride (GaN) have been studied by positron annihilation spectroscopy. It is shown that vacancy defects are formed in Ga or N sublattices depending on the doping of the material. Vacancies are decorated with impurity atoms leading to the compensation of the free carriers of the sam...

The effects of Ga and N vacancy defect on the change in surface feature, work function, and characteristic of Cs adsorption on a (2 × 2) GaN(0001) surface have been investigated using density functional theory with a plane-wave ultrasoft pseudopotential method based on first-principles calculations. The covalent bonds gain strength for Ga vacancy defect, whereas they grow weak for N vacancy def...

The correlation factor for impurity diffusion by a vacancy-mechanism is a function of the vacancy-jump frequencies in the surroundings of the diffusing atom. Since in Si and Ge the vacancy can act as an acceptor, a long-range Coulomb interaction between donor atoms and vacancies exists. The usual assumption, that only a few vacancy-jump frequencies in the im­ mediate surroundings of the vacancy...

Oxygen vacancies in metal oxides are known to determine their chemistry and physics. The properties of neutral oxygen vacancies in metal oxides of increasing complexity (MgO, CaO, alpha-Al2O3, and ZnO) have been studied using density functional theory. Vacancy formation energies, vacancy-vacancy interaction, and the barriers for vacancy migration are determined and rationalized in terms of the ...

Using first-principles calculations, we study the electronic structures of Pt/HfO2 interface in the presence of oxygen vacancy. The energetics and charge transfer are examined when the oxygen vacancy is at various distances from the interface. It is found that the oxygen vacancy is strongly attracted to the interface and the charge transfer decreases monotonically as the vacancy moves away from...

In the present study, the effects of arrangement and distribution of multifarious types of defects on fundamental frequency of carbon nanotubes are investigated with respect to different chirality and boundary conditions. Interatomic interactions between each pair of carbon atoms are modeled using two types of non–linear spring–like elements. To obtain more information about the influences of d...

Hexagonal boron nitride (h-BN) is an electrical insulator with a large band gap of 5 eV and a good thermal conductor of which melting point reaches about 3000 °C. Due to these properties, much attention was given to the thermal stability rather than the electrical properties of h-BN experimentally and theoretically. In this study, we report calculations that the electronic structure of monolaye...

We present calculations of the bound state energy levels of anion vacancies near the surface of a III-V semiconductor. We consider the (110) surface of GaAs, InP, and the Ga1_xAlxAs alloy system. As the vacancy is moved toward the surface, the energy levels are only slightly perturbed until the vacancy reaches the second atomic layer from the surface. At this point, the anion vacancy levels mov...

In this paper, (10, 0) zigzag nanotubes and (6, 6) armchair nanotubes are considered to investigate the effects of randomly distributed vacancy defects on mechanical behaviors of single-walled carbon nanotubes. A spatial Poisson point process is employed to randomly locate vacancy defects on nanotubes. Atomistic simulations indicate that the presence of vacancy defects result in reducing nanotu...