Optical properties of ideal γ-Al<sub>2</sub>O<sub>3</sub> and with oxygen point defects: an ab initio study

Papi, H.; Jalali-Asadabadi, S.; Nourmohammadi, A.; Ahmad, Iftikhar; Nematollahi, Javad; Yazdanmehr, M.

doi:10.1039/c5ra06027c

Cited by 14 publications

(5 citation statements)

References 51 publications

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“…These graphics show that the bandgap of the thin films under question are all zero, since the Im[ε(ω)] spectra start to rise up immediately from zero energy. 53 This, consistent with the DOSs shown in Figure 3 and the Re[ε(ω)] spectra shown in Figure 4a,b, reconfirms that these thin films are all metal. The peaks of the imaginary part of dielectric function, Im[ε(ω)], can give the inter-or intraband Another important optical parameter is the energy loss function (ELF).…”

Section: Resultssupporting

confidence: 87%

“…The imaginary parts of the dielectric functions of the three cases are shown for parallel directions in Figure c and for the perpendicular direction in Figure d. These graphics show that the bandgap of the thin films under question are all zero, since the Im[ε(ω)] spectra start to rise up immediately from zero energy . This, consistent with the DOSs shown in Figure and the Re[ε(ω)] spectra shown in Figure a,b, reconfirms that these thin films are all metal.…”

Section: Resultssupporting

confidence: 78%

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Novel Graphene-like Co₂VAl (111): Case Study on Magnetoelectronic and Optical Properties by First-Principles Calculations

Boochani¹,

Nowrozi²,

Khodadadi³

et al. 2017

J. Phys. Chem. C

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The electronic, magnetic, and optical properties of the Co2VAl (111) graphene-like (GL) monolayer as well as the (101) and (011) terminations have been calculated on the basis of the density functional theory (DFT) and FP-LAPW+lo method. The GL (111) Co2VAl has been grown in the (111)-crystallographic direction, leading to various and interesting physical properties compared to those of their considered directions. The films grown in the (101) and (011) directions have shown metallic behavior with low spin-polarization at the Fermi level, while the GL case has shown a perfect half-metallic behavior with an integer amount of magnetic moment (1.00 μB) and 0.5 eV spin-flip gap. Thus, it can be a good candidate for spintronic applications. Although all of these thin films behave similarly in the ultraviolet region, the GL case appears to be different in the infrared and visible regions. The main plasmonic energies occur in the 12–13.8 eV energy range in the parallel (xx) and perpendicular (zz) directions. Our results show that the incident light cannot propagate in the visible region for all the considered monolayers.

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Section: Resultssupporting

confidence: 87%

Section: Resultssupporting

confidence: 78%

Novel Graphene-like Co₂VAl (111): Case Study on Magnetoelectronic and Optical Properties by First-Principles Calculations

Boochani¹,

Nowrozi²,

Khodadadi³

et al. 2017

J. Phys. Chem. C

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“…Overall, the results for the structural properties are in good agreement with experiments, and HSE and sX-LDA calculations. [28,27].…”

Section: Results: Tm Mono-oxidesmentioning

confidence: 99%

“…In some systems for e.g. (See [27,28]), this might be very crucial especially near the phase trans itions. In order to verify the transferability of the U values, we have tested the electronic structure properties using different pseudo-potentials (ultrasoft [29] and PAW) and also all electron methods.…”

Section: Methodsmentioning

confidence: 99%

Improved electronic structure and magnetic exchange interactions in transition metal oxides

Gopal¹,

Gennaro²,

Gusmão³

et al. 2017

J. Phys.: Condens. Matter

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Abstract. We discuss the application of the Agapito Curtarolo and Buongiorno Nardelli (ACBN0) pseudo-hybrid Hubbard density functional to several transition metal oxides. ACBN0 is a fast, accurate and parameter-free alternative to traditional DFT+U and hybrid exact exchange methods. In ACBN0, the Hubbard energy of DFT+U is calculated via the direct evaluation of the local Coulomb and exchange integrals in which the screening of the bare Coulomb potential is accounted for by a renormalization of the density matrix. We demonstrate the success of the ACBN0 approach for the electronic properties of a series technologically relevant mono-oxides (MnO, CoO, NiO, FeO, both at equilibrium and under pressure). We also present results on two mixed valence compounds, Co 3 O 4 and Mn 3 O 4 . Our results, obtained at the computational cost of a standard LDA/PBE calculation, are in excellent agreement with hybrid functionals, the GW approximation and experimental measurements.

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“…By plotting (ahm) 2 versus photon energy, the energy gap can be obtained by extrapolating the linear part to the (hm = 0) point, as shown in the inset of Fig. 3.The calculation shows that the optical band gap of alumina prepared at 3.5 J/cm 2 was found to be 5.4 eV; this value is lower than that of bulk alumina due to the presence of oxygen vacancies and point defects (Papi et al 2015;Tamboli et al 2011). An abrupt decrease in the optical absorption was observed at *k = 280 nm and seemed to be steady after this wavelength (highly transparent).…”

Section: Methodsmentioning

confidence: 99%

Preparation and characterization of aluminum oxide nanoparticles by laser ablation in liquid as passivating and anti-reflection coating for silicon photodiodes

2017

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In this study, we have prepared aluminum oxide (Al 2 O 3 nanoparticles) NPs with size ranging from 50 to 90 nm by laser ablation of aluminum target in ethanol. The effect of laser fluence on the structural, morphological and optical properties of Al 2 O 3 was demonstrated and discussed. X-ray diffraction XRD results confirm that the synthesized Al 2 O 3 NPs are crystalline in nature. The sample prepared at 3.5 J/cm 2 /pulse exhibits single phase of c-Al 2 O 3 , while the XRD patterns of the nanoparticles synthesized at 5.3 and 7.5 J/cm 2 /pulse show the co-existence of the a-Al 2 O 3 and c-Al 2 O 3 phases. Nanostructured Al 2 O 3 films have been used as anti-reflecting coating and surface passivation layer to improve the photoresponse characteristics of silicon photodiode. The experimental data showed that the optical energy gap decreases from 5.3 to 5 eV as the laser fluence increases from 3.5 to 7.3 J/cm 2 . The lowest optical reflectivity was found for silicon photodiode deposited with a single layer of Al 2 O 3 prepared at 3.5 J/cm 2 /pulse. The effect of laser fluence on the refractive index and extinction coefficient of the nanostructured Al 2 O 3 film was studied. The photosensitivity of the silicon photodiode increased from 0.4 to 1.4 AW -1 at 800 nm after depositing Al 2 O 3 prepared at 3.5 J/cm 2 /pulse, followed by rapid thermal annealing at 400°C for 60 s.

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Optical properties of ideal γ-Al₂O₃ and with oxygen point defects: an ab initio study

Abstract: The optical properties of pure γ-Al2O3 and in the presence of oxygen point defects are investigated by the density functional theory approach using the PBE-GGA and TB-mBJ-GGA schemes.

Cited by 14 publications

References 51 publications

Novel Graphene-like Co₂VAl (111): Case Study on Magnetoelectronic and Optical Properties by First-Principles Calculations

Novel Graphene-like Co₂VAl (111): Case Study on Magnetoelectronic and Optical Properties by First-Principles Calculations

Improved electronic structure and magnetic exchange interactions in transition metal oxides

Preparation and characterization of aluminum oxide nanoparticles by laser ablation in liquid as passivating and anti-reflection coating for silicon photodiodes

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Optical properties of ideal γ-Al2O3 and with oxygen point defects: an ab initio study

Abstract: The optical properties of pure γ-Al2O3 and in the presence of oxygen point defects are investigated by the density functional theory approach using the PBE-GGA and TB-mBJ-GGA schemes.

Cited by 14 publications

References 51 publications

Novel Graphene-like Co2VAl (111): Case Study on Magnetoelectronic and Optical Properties by First-Principles Calculations

Novel Graphene-like Co2VAl (111): Case Study on Magnetoelectronic and Optical Properties by First-Principles Calculations

Improved electronic structure and magnetic exchange interactions in transition metal oxides

Preparation and characterization of aluminum oxide nanoparticles by laser ablation in liquid as passivating and anti-reflection coating for silicon photodiodes

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Product

Resources

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Optical properties of ideal γ-Al₂O₃ and with oxygen point defects: an ab initio study

Novel Graphene-like Co₂VAl (111): Case Study on Magnetoelectronic and Optical Properties by First-Principles Calculations

Novel Graphene-like Co₂VAl (111): Case Study on Magnetoelectronic and Optical Properties by First-Principles Calculations