Molecular Dynamics Analysis of Diffusion of Point Defects in GaAs

Abstract

Molecular dynamics simulation was carried out to estimate the diffusion coefficient and the mechanism of diffusion with a constant pressure and temperature algorithm. The following results were obtained: (i) there is little diffusion of a vacancy in solid GaAs, even near the melting point, (ii) the diffusion coefficient of an interstitial arsenic atom is larger than that of an interstitial gallium atom, (iii) after formation of a dumbbell pair in the ͓110͔ direction, an interstitial arsenic atom migrates in the ͓110͔ direction, while an interstitial gallium atom migrates in either the ͓110͔ or ͓Ϫ110͔ direction, and (iv) an interstitial arsenic atom pushes out a substitutional arsenic atom and then diffuses by an interstitialcy mechanism, while an interstitial gallium atom pushes out either a substitutional arsenic or gallium atom. Finally, all of migrating interstitial atoms in solid GaAs switch to interstitial arsenic atoms at the final stage of diffusion.

Recent Development of Vacancy Formation Energy

“…In the past years, molecular dynamics simulations on the vacancy use two and three-body form of Stillinger-Weber potential model [26] ; With the continuous development of the computer, there has been much closer to the embedded atom method (EAM) of the actual potential,that is many-body potential model [27] , as well as first-principles pseudopotential model [28]. Tomonori Kitashima with his partners [29] , use two and three-body form of Stillinger-Weber pair potential model to analyze vacancy diffusion in gallium arsenide.the study show that even at the melting point, there are still weak solid diffusion, and in the self-interstitial diffusion, the diffusion coefficient of arsenic atoms is larger than that of gallium atoms. Baskes [30] , using a more accessible and fix potential embedded atom method (MWAM) which including the angle of force, study on the simulated Mo / Si system and predict the lattice constant, elastic constants, vacancy formation energy, the phase interface stability.…”

Thermal transport in Si/Ge nanocomposites

“…Furthermore, the thermal properties of single or multi-wall carbon nanotubes have been investigated by using MD widely [20,21]. The MD method is suitable for studying defects such as impurities, voids, pores and grain boundaries in materials [22][23][24][25]. The thermal properties of nanocomposites with and without defects, however, have rarely been studied by using MD simulation.…”