First-principles study of rare gas incorporation in titanium nitride

Abstract

First-principles calculations have been carried out to study the incorporation of rare gas atoms, with a focus on xenon, in titanium nitride. The density functional theory-generalized gradient approximation method has been used to calculate the formation energy of several point defects (vacancies, interstitials, divacancies, Frenkel pairs) and then the incorporation energies of rare gases in these defects. The main results show that nitrogen vacancies are the most probable defects as well as the Schottky defects. Incorporation energy calculations suggest that the most favorable Xe host sites involve vacancies as the Schottky defect with vacancies located on the edge of the cubic lattice.

First-Principles Energetics of Some Nonmetallic Impurity Atoms in Plutonium Dioxide

“…1,23,53,54 Apart from the theoretical schemes, different definitions of defect energetics can lead to discrepancy. Generally, the terminology "formation energy of defect", denoted as E f , is more widely used than "incorporation energy", denoted as E i .…”

On the nature of point defect and its effect on electronic structure of rocksalt hafnium nitride films

“…For example, the difference between the formation energies of the interstitials calculated by the 64-atom and 96-atom supercells is not more than 0.1 eV. The formation energies (E F ) of the single N-related point defects can be defined as [8,13,42] …”

“…To date, some research on point defects for d-TiN x [7,8,23,26,[28][29][30], d-ZrN x [23,31] and d-HfN x [19,32] films, prepared by magnetron sputtering or pulsed laser deposition, have been performed, in which the researchers have consistently found that N vacancies are the primary point defects in sub-stoichiometric d-TMN x . However, for overstoichiometric d-TMN x films, certain disagreement exists in the assignment of primary point defects, in which most investigations have agreed that metal vacancies are primary point defects in both over-stoichiometric d-TiN x and d-ZrN films, whereas a few researchers have proved that nitrogen interstitials are dominant point defects in TiN x films.…”

“…Their excellent properties, including high hardness, thermal stability, IR reflectance, electrical conductivity, corrosion resistance and good diffusion barrier [1][2][3][4][5], make them very promising candidates for applications in wear-resistant coatings [2][3][4], solar control coatings on windows [6,7], decorative coatings [6,8], highly reflecting back contacts in solar cells [2,9] and LED devices [10], field effect transistor metal gates [1,11] and diffusion barriers in microelectronics [1,2,12]. In d-TMN x films, the point defects related to stoichiometry x commonly exist, because it is difficult to obtain the nominally stoichiometric films experimentally.…”

Experimental evidence of Xe incorporation in Schottky defects in UO2

“…3 Due to their insolubility in solids and their chemical inertness, noble gases can conveniently be used as a probe for chemical, physical, and structural changes in a wide range of materials as glasses, 4 semiconductors and metals, 5 as well as ceramics. 6 In particular, xenon can be used to investigate the microporosity distribution in materials. 7 In the uranium dioxide nuclear fuel (UO 2 ), xenon is an abundant fission product.…”