Nitrogen Trapping Ability of Hydrogen-Induced Vacancy and the Effect on the Formation of AlN in Aluminum

Duy Vo,Thoi Nguyen,Truong Nguyen,Aleksey Lipnitskii

doi:10.3390/coatings7060079

Abstract

This paper presents the ternary interaction of N, H, and vacancy point defects and the nitrogen trapping ability of aluminum vacancies induced by hydrogen by means of DFT methods employed in VASP (Vienna Ab initio Simulation Package) and Abinit packages. The obtained vacancy formation energy of 0.65 eV is close to experimental values. Although the N–vacancy complex is unstable with the negative binding energy of −0.51 eV, the stability of H–vacancy–N is proved by the positive binding energy of 0.59 eV and the appearance of the orbital hybridization in the density of state (DOS) of atoms connecting to this complex. Moreover, Al vacancies can trap more than 4 N atoms, which prevents the formation of aluminum nitride and subsequently affects not only the hardness of the Al surface but also many practical applications of AlN coating.

Highlights

Aluminum and its alloys are widely used in life and technique
The DFT calculation of Abinit and VASP packages was performed to study the effect of H and N
There are differences in the values given by Abinit and VASP packages, both packages describe the same manner of H, N, and Al vacancy interaction: i

Summary

Introduction

Aluminum and its alloys are widely used in life and technique. The aluminum coated with an AlN layer can be used to improve LED performance [1,2], or it can be used as electronic packaging material [3,4]. AlN can be used as protective coatings [5,6]. The formation of AlN is often affected by point defects such as vacancies and light impurities. There have been many studies on the effect of separate impurities on the vacancy formation and nucleation in Al [7,8,9]. In the experimental studies of Chung et al [10], they found that the hardness of the Al sample seems to hardly increase during nitrogen implantation at the fluence of 2 × 1018 ions/cm

Methods

Results

Conclusion