R. H. Athab, B. H. Hussein^*

Chalcogenide Letters, Vol.20, No.7, pp. 477-485, 2023, DOI:10.15251/CL.2023.207.477

Abstract Zinc Telluride ZnTe alloys and thin film have been fabricated and deposited on glass substrates by thermal evaporation method which may be a suitable window layer of zinc telluride with different annealing temperatures (373 and473) K for 60 minutes in vacuum. Deposited thin films with thickness 100 nm was characteristic by using X-ray diffraction XRD to know structures, Atomic Force Microscopy (AFM) to evaluate surface topology, morphology. It was found out that the vacuum annealing improves on thin ZnTe films structure and surface morphology. Structural analysis reveals that ZnTe films have zinc blende structure of More >

E. Lu^*, M. Q. Wu, L. L. Dai, X. Y. Xu

Chalcogenide Letters, Vol.20, No.7, pp. 469-476, 2023, DOI:10.15251/CL.2023.207.469

Abstract This study used a simple one-step hydrothermal method to synthesize the MoS₂/GR composites with a new morphology composed of graphene nanotubes and ultra-thin molybdenum disulfide with the help of sodium chloride. The composites were characterized by XRD, XPS, SEM, TEM, and a series of characterization methods. Meanwhile, the tribological properties of the composites were studied. The results show that the addition of 1% MoS₂/GR composite nanotubes has excellent tribological properties. In addition, the structure and excellent tribological properties of MoS₂-C- nanocomposite lubrication materials will be conducive to designing new nanomaterials with 2D/3D structures, enhancing the anti-friction and More >

M. K. Butt^a, S. Saleem^a, F. F. Al-Harbi^b, S. Atta^a, M. Ishfaq^a, F. S. Al Juman^c, M. Yaseen^a,*

Chalcogenide Letters, Vol.20, No.7, pp. 459-467, 2023, DOI:10.15251/CL.2023.207.459

Abstract The full potential linearized augmented plane wave (FP-LAPW) approach based on the density functional theory (DFT) is employed to know the effect of Co doping on the electronic, optical, and magnetic characteristics of BaTi_1-xCo_xO₃ at x= 8.33%, 16.66%, 25%, and 50%. The computed spin-polarized electronic band structure (BS) and the density of states (DOS) elucidate that the BaTi_1-xCo_xO₃ compound has a ferromagnetic semiconductor behavior at all doping concentrations. The results indicate that the magnetic moment in BaTi_1-xCo_xO₃ is found due to the p-d hybrid orbitals of Co. Moreover, the optical features of the Co-doped BTO compound are More >

J. S. Mohammed^a,*, F. K. Nsaif^b, Y. M. Jawad^a, K. A. Jasim^b, A. H. Al Dulaimi^a

Chalcogenide Letters, Vol.20, No.7, pp. 449-458, 2023, DOI:10.15251/CL.2023.207.449

Abstract In this work, As₆₀Cu_40-xSe_x thin films were synthesized, and the pulsed laser deposition method was used to study the effected partial replacement of copper with selenium. The electrical characteristics and optical characteristics, as indicated by the absorbance and transmittance as a function of wavelength were calculated. Additionally, the energy gap was computed. The electrical conductivity of the DC in the various conduction zones was calculated by measuring the current and voltage as a function of temperature. Additionally, the mathematical equations are used to compute the energy constants, electron hopping distance, tail width, pre-exponential factor, and density More >

Z. Liu^a,*, R. X. Wang^a, K. W. Sun^b, X. C. Ling^b, J. W. Sun^b, D. H. Chen^c

Chalcogenide Letters, Vol.20, No.7, pp. 439-447, 2023, DOI:10.15251/CL.2023.207.439

Abstract Gd₂O₃:Er³⁺ @Gd₂O₃:Yb³⁺ core-shell nanofibers with cubic phase were successfully fabricated by electrospinning method. The structural, morphological properties were investigated by X-Ray diffraction, scanning electron microscopy. Under 980 nm excitation, the upconversion photoluminescence in visible light exhibits strong red emitting band with obvious splitting peaks resulted from stark splitting of energy level. The visible emissions are sensitive to temperature in the range of 303-543 K. The red emission displays quenching with elevation of temperature. The activation energy for thermal quenching is equal to 0.1408 eV. The temperature dependent multi-peaks of red emission were systematically investigated. Based on More >

M. L. Han^*, Y. Hu

Chalcogenide Letters, Vol.20, No.8, pp. 619-628, 2023, DOI:10.15251/CL.2023.208.619

Abstract Hydrostatic pressure is an effective tool that can give rise to novel crystal structures and physical properties. In this paper, we perform the first-principles calculation based on density-functional theory (DFT) to study the structural, electronic, elastic, and optical properties of chalcogenide perovskite SrZrS₃ under pressure. The results indicated that both the lattice constant and cell volume decrease with the increase of pressure, which are matched well with available previous values. The obtained elastic constants reveal the SrZrS₃ is mechanically stable between 0 and 15 GPa. Additionally, the main features of the valence and conduction bands have More >

Y. Benkrima^a,*, D. Belfennache^b, R. Yekhlef^b,c, A. M. Ghaleb^d

Chalcogenide Letters, Vol.20, No.8, pp. 609-618, 2023, DOI:10.15251/CL.2023.208.609

Abstract Our calculations have been done using the density functional theory (DFT). In fact, we were able to find the optical and structural properties of CdSe compound of cubic phase by using the previously mentioned theory. The pseudo-potential linearised augmented plane wave (PP-LAPW) method is applied to solve the Kuhn-Sham equations. The results are obtained using Generalized Gradient Approximation according to the scheme described by Perdew-Burke-Ernzerhof (GGA-PBE) as a types of exchange-correlation. Convergence of energy and charge has been verified, this is for the study of properties basic state of the compound. It was found that… More >

K. A. Mohammed^a,*, N. H. J. Al Hasan^b, L. R. Al-Ameer^c, D. S. Abdul-Zahra^d, Y. D. Dwivedi^e, K. H. Salem^f, M. K. Agarwal^g, R. S. Zabibah^h, M. A. Alkhafajiⁱ

Chalcogenide Letters, Vol.20, No.8, pp. 599-608, 2023, DOI:10.15251/CL.2023.208.599

Abstract This study examined the properties of polyvinyl alcohol (PVA) as a matrix composite, specifically focusing on the characterization techniques of UV-Visible spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDX). The investigation centered around a novel hybrid structure composed of CdZnS nanoparticles implanted within a composite matrix of PVA and Fe₂O₃. The analysis of microstructure data provided evidence of the influence of CdZnS nanoparticles on the structural characteristics of PVA–Fe₂O₃. The composites that were synthesized exhibited significant absorption peaks at wavelengths of 233 nm and 234 nm for PVA-Fe₂O₃ and PVA-Fe₂O₃-CdZnS, respectively. More >

Z. Hadef^a,*, K. Kamli^a, O. Kamli^b, S. Labiod^a

Chalcogenide Letters, Vol.20, No.8, pp. 587-597, 2023, DOI:10.15251/CL.2023.208.587

Abstract Ultrasonic Spray Pyrolysis (USP) was used to deposited Co doped SnS₂ thin films on a glass substrate at different substrate temperatures (Ts = 350 °C, 375 °C, 400 °C, and 425 °C). DRX patterns shows that the synthesized films revealed a pure SnS2 phase with hexagonal structure. The mean crystalline grain sizes were showed an increasing– decreasing trend between 15.67 and 29.84 nm with an increment in the substrate temperature. The SEM images were significantly affected by the substrate temperature. Also, the optical band gap increases from 2.62 to 3.00 eV with the substrate temperatures increasing. More >

Y. Zhang^a, J. Guo^a, Y. W. Zhang^a, Q. Y. Zou^a,b,c,*, S. R. Zhang^d,*, Q. Lai^e

Chalcogenide Letters, Vol.20, No.8, pp. 579-586, 2023, DOI:10.15251/CL.2023.208.579

Abstract We investigated the structural, electronic, chemical bonding, and optical properties of β-AgBiS₂ crystal by using the Perdew-Burke-Ernzerhof (PBE) functional and the hybrid functional Heyd Scuseria Ernzerhof (HSE) within the DFT formalism. The electronic band structures obtained by both methods indicate that β-AgBiS₂ is an indirect band gap semiconductor with band gap of 0.571 and 1.025 eV, respectively. The electron density difference and Mulliken overlap population show that the Ag-S bonds and Bi-S bonds are both ionic bonds. The calculated optical absorption spectrum prove that β-AgBiS₂ is a promising material for solar photovoltaic conversion. More >