QC484 : Study of Electronic Structure and Optical Properties of Silicon Nitride Nanostructures
Thesis > Central Library of Shahrood University > Physics > MSc > 2019
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Abstarct: In this thesis, the electronic structure and optical properties of silicon nitride (Si 3 N 4 )
semiconductors in β - phase (hexagonal), were investigated. The calculations were carried out
baxsed on density functional theory (DFT) using wien2k code and the generalized gradient
approximation( GGA) and local density approximation(LDA) for bulk, pure and Oxygen (%6.25,
%12.5 and %25)-doped β−Si3N4 nano-sheets. For these purposes, the band structure and density
of states (DOSs), real and imaginary parts of the dielectric function, refraction coefficient,
extinction and absorption coefficients, reflectivity, optical conductivity, and electron energy- loss
function were investigated.
Our results showed that bulk β−Si 3 N 4 has an indirect bandgap. Using GGA and LDA the
calculated bandgap was in the range of 4.2 and 4.18 eV, respectively. In β−Si3N4 nano-sheets
the bandgap was converted to direct. This calculated direct bandgap was about 3.5 and 3.2 in
GGA and LDA, respectively. In O- doped β−Si3N4 nano-sheets some impurity bands related to
Oxygen atoms appeared in the bandgap around the Fermi level. Moreover, the bands in the
valance band and the conduction band of the doped β−Si3N4 compared to the un-doped samples
were condensed.
Keywords:
#Density Functional Theory (DFT) #Generalized Gradient Approximation ( GGA) #Local Density Approximation(LDA) #Silicon Nitride(3N4) #Band structure #Density of States (Dos) #Optical Properties #Electronic Structure #β−Si3N4 Nano-sheets #O- doped β − Si3N4 Nano-sheets Link
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
Visitor: