An Ab Initio Study of Atomic Hydrogen and Oxygen Adsorptions on Armchair Silicon Nanotubes

Abstract

First principles calculations based on hybrid density functional theory have been used to study the electronic and geometric properties of armchair silicon nanotubes from (4 4) to (12 12). Full geometry and spin optimizations have been performed without any symmetry constraints with an all electron 3-21G * basis set and the B3LYP functional. The largest silicon nanotube studied has a cohesive energy of 3.47 eV/atom. Atomic hydrogen and oxygen adsorptions on a Si(6 6) tube have been studied by optimizing the distances of the adatoms from both inside and outside the tube. The on-top external site is the most preferred site for hydrogen with an adsorption energy of 6.00 eV and an optimized distance of 1.50 A. For oxygen, the external normal bridge site is the most preferred site with an adsorption energy of 9.68 eV, the optimized distance being 1.66 A. In contrast to some published results, HOMO-LUMO gaps decrease for H adsorption but remain about the same for O adsorption. Radial buckling increases significantly due to H and O adsorptions.

The transport properties of silicon and carbon nanotubes at the atomic scale: a first-principles study

“…The Si-Si bond lengths for the Si(3,3) are 2.25-2.27 Å with a diameter of about 6.51 Å. In addition, the total length of the Si (3,3) in this paper is about 15.62 Å (the main geometrical parameters are shown in Table 1). These results are in good agreement with other studies for SiNTs through hydrogen atoms termination.…”

“…Hence, the electronic band structures of the Si(3,3) near the Fermi level together with the projected density of states (PDOS) approach have been calculated and are presented in Fig. 3 showing the conducting properties of Si (3,3). Moreover, there are other several bands near the Fermi level until AE1 eV, and they will contribute greatly to the charge transport of Si (3,3) through the introduction of a bias voltage.…”

“…It is widely believed that silicon nanotubes (SiNTs) will be one of the next-generation materials that are miscible and compatible with contemporary micro-and nanoelectronic devices, sharing the same origin as silicon. [1][2][3][4][5][6] Substantial efforts have been focused on investigating the electronic and optical properties of SiNTs, both for the purpose of further miniaturizing current integrated electronics and for the hope of unveiling new photonic properties on the same Si chip. Initially, the structure and stability of silicon nanotubes (SiNTs) had been discussed theoretically, [7][8][9][10][11] successfully predicting the possibility of the existence of single-wall silicon nanotubes.…”

Spin Polarization of Electrons in Metallohedral B24N24 Nanocage: A Density Functional Theory Investigation

“…As distinct from the binding energy (−0 543 eV), the strong interaction of Al with B 24 N 24 leads to significant electron transfer from the metal to the B 24 N 24 nanocage. [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] Table I shows the levels of energy for the empty B 24 N 24 and the endohedral B 24 N 24 nanocages. It was clearly found that the empty B 24 N 24 nanocage does not show the effects of spin splitting so the gap of energy between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of B 24 N 24 is the same (4.431 eV) for the majority spin or the minority spin.…”

Chemi-Inspired Silicon Allotropes—Experimentally Accessible Si9 Cages as Proposed Building Block for 1D Polymers, 2D Sheets, Single-Walled Nanotubes, and Nanoparticles

“…SiNTs are promising candidates for the next-generation materials of micro- and nano-electronic devices [ 32 , 33 , 34 ], as they have, for example, better performance with respect to electronic transport [ 35 ], and they are able to produce a current of about one order of magnitude higher than CNTs [ 36 ]. SiNTs have been obtained for the first time from thin solid Si films in 2001 and have directly been synthesized by chemical vapor deposition in 2002 [ 37 , 38 ], and later by molecular beam epitaxy on porous alumina and by self-organized growth of SiNTs with smaller diameter via hydrothermal synthesis [ 39 , 40 , 41 ].…”