Title:Electronic and Optical Properties of Na, Mg, and Al Substituted Zinc-oxide Nanotube: An Insight DFT Study
Volume: 18
Issue: 2
Author(s): Haidar Howari, Ziaul Raza Khan, Mohd Imran, Mohd. Shakir and Md. Shahzad Khan*
Affiliation:
- Department of Physics, Jamia Millia Islamia (A Central University), New Delhi 110025, India
Keywords:
Density functional theory, bandstructure, partial density of states, optical descriptors, absorption coefficient, charge analysis.
Abstract:
Background: The present work deals with DFT-based theoretical investigations
on pristine and metal (M = Na, Mg, and Al) substituted zinc oxide nanotube (MZnONT).
The investigation advocates a change in the electronic bandgap of ZnONT on
the respective substitution of Zn with Na, Mg, and Al. The forbidden energy gap vanishes
on Na incorporation, while Al substitution brings the gap to 0.08eV. The formation
energy calculations suggest the feasibility of these metallic substitutions, of
which Na incorporation is most favorable. Partial density of state (PDOS) analysis is
well correlated with band structures. A localized state above the Fermi level contributed
from Al-3p in Al-ZnONT suggests the electronic affinity of Al-ZnONT for incoming
nucleophiles. Our optical investigation shows large ε1(ω) values in far-infrared (IR) and
visible (Vis) regions for M-ZnONT. Hence, suggests a high refractive index for the
metal-substituted ZnONTs in the prescribed range. The study suggests that photonic energy
loss due to attenuation, bending, and absorption are weak in ultra-violet (UV) and
far UV regions i.e, (3eV to 8eV). However, for the respective energy range, high reflectivity
is predicted. This indicates the nanotubes as a good reflector for the purpose of
coating material surfaces where high reflection is demanded.
Objective: Finding electronic and optical properties of functionalized ZnONT using
DFT method.
Methods: All calculations have been performed in the framework of density functional
theory (DFT) using Troullier Martins’s norm-conserving pseudo-potential.
Results: Metal incorporation at the surface of ZnONT consequent intense ε1(ω) values
in far infra-red and visible regions for M-ZnONT.
Conclusion: The investigation suggests that the metal-substituted nanotube is a good
reflector for coating material surfaces where high reflection is demanded.
