Research Article
Computational Materials & Modelling
Thaizy Carlos Nossa; Paulo José Pereira de Oliveira
Abstract
Carbon nanotubes are allotropes of carbon and are 1D nanomaterials with various applications, including their use as sensors, in composites, and even as drug delivery vectors. In this study, we employed density functional theory with a local density approximation, implemented in the SIESTA software, ...
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Carbon nanotubes are allotropes of carbon and are 1D nanomaterials with various applications, including their use as sensors, in composites, and even as drug delivery vectors. In this study, we employed density functional theory with a local density approximation, implemented in the SIESTA software, to analyze the electrical properties of the chiral (6,3) carbon nanotube containing 48 carbon atoms. We performed studies on energy bands and total and partial density of states. Systems doped with Boron and Nitrogen were investigated, as well as simulations of defects (vacancies). Our results indicate that the nanotube exhibits semiconducting behavior with a bandgap of 0.115 eV. However, after the inclusion of Nitrogen, Boron, and vacancy impurities, its character changes to metallic, with energy bands crossing the Fermi level. The density of states analysis revealed that the carbon 2p orbitals contribute the most to charge mobility compared to the 2p orbitals of Boron and Nitrogen, and also when vacancies are included

Research Article
Nanomaterials & Nanotechnology
Indradevi P; Karunamoorthi R; Sivabharthy M; Ramachandran K
Abstract
Dendrite shaped PbTe, SnTe nanorods and their nanocomposites were successfully synthesized via a simple hydrothermal method using hydrazine hydrate as a reducing agent. The formation of nanostructures was confirmed by high resolution transmission electron microscopy (HRTEM) in both the samples. A detailed ...
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Dendrite shaped PbTe, SnTe nanorods and their nanocomposites were successfully synthesized via a simple hydrothermal method using hydrazine hydrate as a reducing agent. The formation of nanostructures was confirmed by high resolution transmission electron microscopy (HRTEM) in both the samples. A detailed study on dielectric properties of these samples in the frequency range of 50 Hz–50 MHz at various temperatures (50-100 C) shows a tremendous enhancement in PbTe and SnTe nanostructures compared to bulk. But in the case of composite system PbTe: SnTe have significantly lower dielectric constants than pure samples due to no additional percolation threshold in the system. Additionally, the potential mechanism behind the formation of dendrite-shaped PbTe is discussed. Raman spectroscopy further validated the presence of Sn within the PbTe system. The synthesized PbTe and SnTe nanostructures are capable of significantly enhancing the dielectric constant compared to their bulk counterparts, making them suitable for super capacitor applications.
