Energetic evaluation of possible interstitial compound formation of BaSi₂with 2p-, 3s-, and 3d-elements using first-principle calculations

Abstract

The energy changes in the formation of interstitially doped BaSi2, caused by doping with Na, Mg, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, B, C, N, O, F, and Ne, are calculated using the Perdew–Wang generalized gradient approximations of the density functional theory. It is predicted that the majority of the elements, apart from Na, Mg, Zn, and Ne, are capable of forming interstitially doped compounds with BaSi2, if these elements are provided as an isolated atom. However, the energetic stabilities of the standard states of these elements (metals, diatomic gases, etc.) exceed the energy gain accompanying the formation of the interstitial compounds and, therefore, the conventional diffusion method using metals or gaseous source materials cannot produce the interstitial compounds. From the energetic perspective, B, C, N, O, and F appear to be favorably inserted into the BaSi2 lattice, but the observed behavior of B-implanted BaSi2 suggests that substitution of B for Si may occur.

Exploring the potential of semiconducting BaSi2for thin-film solar cell applications

“…During such a long storage period, O are considered to incorporate into the BaSi2 layers. First-principles calculation reveal that the O atoms are supposed to be positioned at the interstitial sites called the 4c sites rather than substitutional sites, differently from Group 13 or 15 elements, and do not create localized states within the band gap [101]. This is perhaps one of the reasons why O, which may interact strongly with BaSi2, seems to have no detrimental effect on the performance of solar cells.…”

Recent advances in computational studies of thin-film solar cell material BaSi2

“…By contrast, theoretical studies are limited. 78) Here, we show our first-principles studies for the effects of external doping in BaSi 2 . There are two possibilities for p-type doping in BaSi 2 : (i) substituting Si with a trivalent element such as B, Al, Ga, and In, or (ii) substituting Ba with a monovalent element such as Li, Na, or K. Similarly, there are two choices for obtaining n-type doping in BaSi 2 : (i) substituting tetravalent Si with a pentavalent element such as N, P, As, or Sb, or (ii) substituting divalent Ba with a trivalent element, such as La or Y.…”

Changes of the band structure of Mg2Si induced by interstitial doping with nonmetallic elements

“…We also had to ensure consistency with our previous studies on Mg 2 Si and other semiconducting alkaline-earth and alkali metal silicides. [4][5][6][7][8][9][10][11][12][21][22][23][24][25][26][27][28][29][30][31] The kinetic cutoff energy for the plane wave expansion of the wavefunctions was set at 380 eV, corresponding to a fast Fourier transformation grid of 36 × 36 × 36. The Monkhorst-Pack (M-P) scheme 32) was used for k-point sampling for the total energy calculations with spacing of 0.4 nm −1 in the reciprocal space, which corresponded to mesh parameters of 4 × 4 × 4 and produced 32 points sampled from the irreducible part of the Brillouin zone.…”