Ab’initio studies of the structural and electronic properties for single-walled armchair MgONT, SiCNTs and ZnONTs for next generations’ optoelectronics

Abstract

Due to greater demand to use 1D semiconducting chips to replace semiconductors made from bulk structures We studied the structural and electronic properties of free (7, 0) metallic oxides and non-metallic carbide nanotubes. SWMgONT, SWZnONT and SWSiCNT were chosen as the representative model. All the quantum simulation studies were done within DFT ab’initio implemented in quantum ESPRESSO. Results obtained for structural properties revealed that the most stable bond lengths of MgONT, ZnONT and SiCNT are 1.80 Å, 1.82 Å and 1.42 Å respectively. The results obtained revealed 2.8 eV band gap for SWMgONT, 0.5 eV for SWZnONT and 0.8 eV for SWSiCNT respectively. Furthermore SWMgONT and SWZnONT are regarded as direct band gap semiconductors while SWSiCNT is regarded as an indirect semiconductor with narrow band gap. The narrow band gap of all the three systems obtained demonstrates their potential in the optoelectronic application in the next generations’ sustainability science and technology. Recent studies showed that explorations were conducted on oxide nanotubes such SiO2NT, however to the best of our knowledge, studies of the oxide nanotubes of Mg, Zn and Si have not been reported, hence few literature are available.

The potentials of boron-doped (nitrogen deficient) and nitrogen-doped (boron deficient) BNNT photocatalysts for decontamination of pollutants from water bodies

“…The efficiency rate of photocatalysts depends on their light absorption properties which are dependent on the imaginary dielectric constant. 20 We define the optical response of photocatalyst materials to the incident solar radiation in terms of the real and imaginary dielectrics as 21 ε ( ω ) = ε 1 ( ω ) + ε 2 ( ω )where ε 1 ( ω ) is the real part and ε 2 ( ω ) is the imaginary part of the optical dielectric constant. The real part of the dielectric function takes care of the photon energy dispersion, while the imaginary part of the dielectric function describes the photon energy absorption.…”

“…The efficiency rate of photocatalysts depends on their light absorption properties which are dependent on the imaginary dielectric constant. 20 We dene the optical response of photocatalyst materials to the incident solar radiation in terms of the real and imaginary dielectrics as 21…”

DFT Studies of the Photocatalytic Properties of MoS2-Doped Boron Nitride Nanotubes for Hydrogen Production

“…Although both results fall within the band gap range of the photocatalyst, the GGA value was an underestimate, while the G 0 W 0 value gives the exact band gap obtained. Furthermore, the band gap obtained is direct since VBM and CBM all have the same momentum . As can be seen, the CBMs of the MoS 2 -doped SWBNNT are larger than the H + /H 2 potential (−4.40 eV), so they are suitable photocatalysts for the half-reaction of hydrogen reduction .…”

“…Furthermore, the band gap obtained is direct since VBM and CBM all have the same momentum. 27 As can be seen, the CBMs of the MoS 2 -doped SWBNNT are larger than the H + /H 2 potential (−4.40 eV), so they are suitable photocatalysts for the half-reaction of hydrogen reduction. 28 Based on the obtained results, it can be shown that the (12,12) MoS 2 -doped SWBNNT semiconductor can be an excellent candidate for enhanced photocatalytic water splitting.…”

First-Principle Studies of the Structural, Electronic, and Optical Properties of Double-Walled Carbon Boron Nitride Nanostructures Heterosystem under Various Interwall Distances

“…Te quasi-particle band gaps are formed from the weak interactions of SWCNT and SWBNNT atoms which are renormalized to smaller values in the presence of dielectric substrates of boron nitride nanotubes [22]. Te narrowing of the band gap is due to the polarization-induced screening efects which change the correlation energy of the SWCNT orbitals which stabilizes the valence band [23].…”