Abstract
This research study focused on layer-by-layer modeling of a ternary nanomaterial from Al2O3, CaO, and an Armchair carbon nanotube (CNT) with a chirality vector (3,3). These three different materials were combined at the nanoscale to discover possible novel and useful properties for application in electronics, batteries, fuel cells, and other energy storage devices. As a result, the electrical structure and properties (which entails the band gap, density of state, and band structure), and the mechanical properties (which entails the shear modulus, young modulus, hardness, bulk modulus, and compressibility) of the modeled Al2O3-CaO-CNT(3,3) nanomaterial had been looked into through density functional theory (DFT). In order to have an adept understanding of controlled applications, the electrical structure and properties were investigated with variation in temperatures at 0 ℃, 25 ℃, 40 ℃, 60 ℃, 80 ℃, and 100 ℃, respectively. The mechanical properties were investigated along (100), (0-10), and (211) orientations respectively. The Perdew, Burke, and Ernzerh (PBE) of exchange-correlation functional is an all-electron (AE) technique with generalized-gradient approximation (GGA), which was the adopted fundamentals for all the calculations done in the research work for the nanomaterial.
Al2O3-CaO-CNT(3,3) displayed an outstanding energy gap (EG) of 0.000 eV and 0.007 eV (which is not far conductors) for the downward and upward spin, respectively, lower than the Al2O3 energy gap, which is used mostly for insulation application. Nevertheless, the nanomaterial energy gap was found to reduce with a rise in temperature from 0 ℃ to 100 ℃ which synchronizes with the models with approximate regression values of 1. Al2O3-CaO-CNT(3,3) was also demonstrated to be mechanically stable as its anisotropic shear modulus of 9.412 GPa and Young's modulus of 20.234 GPa is much better than that of multi-wall CNT, although lesser than the shear modulus and Young's modulus of alumina (Al2O3).
Also, it is impossible to develop perfect Al2O3-CaO-CNT(3,3) nanomaterial even when a sophisticated technique like atomic layer deposition is used for the material development. Therefore, this study also investigated the effects of defects like oxygen vacancy (Vo), aluminium vacancy (VAl), and calcium vacancy (VCa) on the structural, mechanical, and electrical properties of the modeled nanomaterial. This was achieved by achieved by introducing single Vo, VAl, and VCa into separate nanostructures, respectively before investigating the properties numerically using DFT.
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VAl in the nanomaterial changed the energy gap from 0.007 eV and 0.000 eV to 0.560 eV and 0.129 eV for spin up and spin down, respectively. Vo in the nanomaterial changed the energy gap from 0.007 eV and 0.000 eV to 0.522 eV and 0.139 eV while VCa changed the energy gap to 0.922 eV and 0.046 eV for spin up and spin down, respectively.
The presence of VAl, VO, and VCa in the nanomaterial also led to the degradation of some of the mechanical properties majorly along (100), (0-10), and (211), respectively. For instance, in the present of VAl, along (0-10), the maximum bulk modulus degrades from 48.73GPa to 8.40GPa, and the compressibility also degraded from 56.82GPa to 90.68GPa.