Publications Internationales

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    Phase Transition and Atomic Distances Behavior of ZnO Rocksalt Structure under Extended Pressure: a Parallel and Equilibrium MD Computation Yahia Chergui
    (Preprints, 2023) Chergui, Yahia; Ouatizerga, Abd elaziz; Salah, Essma Redouane
    Zinc oxide (ZnO) as a semiconductor in its crystalline or amorphous form is still a promised material, especially under isobaric and isothermal ensembles. In this work, Parallel and Equilibrium Molecular Dynamics and DL_POLY_4 software are employed to predict the relationship between the behavior of ZnO chemical bonds and the phase transition literatures, using correlation function g(r) of Zn-Zn, Zn-O, and O-O pairs. Our system is composed of 5832 atoms of ZnO rocksalt structure (2916 atoms of Zn2+ and 2916 atoms of O2-), under the temperature of 300 (K) and the range of pressure 0-400 (GPa). The lengths of ZnO bonds, the standard error, standard deviation, the maximum of g(r), and the percentage of the variation of the bonds are analyzed. The interatomic interactions are modeled by the potential of Buckingham for short-range and Coulomb for long-range interactions. The calculations were run on the RAVEN Supercomputer of Cardiff University (UK). Our data are mostly in the vicinity of available information of bonds lengths; the rest can be deduced from the pressure of phase transition to use it as a new approach of phase transition confirmation. However, the rest of our results are still a prediction because of no results under extended pressure used in this work. These data have huge importance, as it is required to be used in many industrial sectors, geophysics, Medicine, and Pharmacy, especially in nanoscale and materials design.
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    Dependence of structural and optical properties of ZnO thin films grown by Sol–Gel Spin-Coating technique on solution molarity
    (Springer, 2022) Chala, Slimane; Bdirina, Madani; Elba, Mourad; Naoui, Yassine; Benbouzid, Yazid; Taouririt, Taki Eddine; Labed, Mohamed; Boumaraf, Rami; Bouhdjar, Abdel Fodhil; Sengouga, Nouredine; Yakuphanoğlu, Fahrettin; Rahmane, Saâd
    Zinc oxide (ZnO) thin films were deposited on glass substrates by using sol–gel spin coating technique. Zinc acetate dihy- drate and 2-methoxyethanol were used as precursor with different molar concentrations, 0.2 M, 0.3 M and 0.6 M. The effect of precursor concentration on the structural and optical properties, transmission (T), reflection (R), optical bandgap (Eg), Urbach energy (E U ), refractive index (n), extinction coefficient (k), single-oscillator energy (E 0 ), dispersion energy (E d ), moments M −1 and M −3 , dielectric constant (ε) and optical conductivity (σ), of the ZnO thin films was studied and investi- gated. Although, the transmittance, slightly, decreased and the reflectance increased, as the molar concentration increased, the measurements showed that all samples have high transparency and low reflectivity in the visible range which make them suitable for solar cells applications. It is also found that, as the molarity increased, the ZnO thin films exhibited lower Eg and E U and higher Ed, M −1 and M −3
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    Behavior of phase transition of ZnO in nanoscale of time a molecular dynamics computation
    (IOP Publishing, 2021) Chergui, Yahia; Aouaroun, Tahar; Hadley, Mark J; Chemam, Rafik; Ouatizerga, A.
    The phase transition of Zinc Oxide Wurtzite structure is investigated at the nanoscale of time using Equilibrium time of total energy in isobaric and isothermal ensemble. The calculations ran on the RAVEN supercomputer of Cardiff University employing Molecular Dynamics simulation and DL_POL_4 software, the short and long-range interatomic interactions modeled by Bukingham-Coulomb potential. In this work we used low and high range of pressure and temperature of 0-30 GPa and 40-200 GPa, and 300-500 K and 1500-3000 K respectively. Although no data about confirming phase transition using equilibrium time of total energy as our knowledge, our results are in agreement with the classical method but are still a prediction which needs experimental confirmation. This work has great importance in nanotechnology and many industrial and academic sectors
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    Effect of Er3+ doping on structural, morphological and photocatalytical properties of ZnO thin films
    (IOP Publishing, 2018) Bouhouche, S.; Bensouici, F.; Toubane, Mahdia; Azizi, A.; Otmani, A.; Chebout, K.; Kezzoula, F.; Tala-Ighil, Razika; Bououdina, Mahdia
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    Characterization and studying of ZnO thin films deposited by spray pyrolysis : effect of annealing temperature
    (Elsevier, 2016) Belkhalfa, H.; Ayed, H.; Hafdallah, A.; Aida, M.S.; Tala-Ighil, Razika
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    Photoluminescence and structure of ZnO films deposited on i substrates by chemical spray deposition
    (2009) Sali, S.; Tala-Ighil, Razika; Kermadi, Salim; Kechouane, M.; Boumaour, Messaoud
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    The effect of growth conditions, point defects and hydrogen on the electronic structure and properties of p-type (Al,N) codoped ZnO: A first principles study
    (Elsevier Ltd, 2015) Lahmer, Mohammed Ali; Guergouri, K
    Abstract The effects of point defects, hydrogen, and growth conditions on the electronic structure and properties of the (Al,N) codoped p-type ZnO have been investigated using the first principles method. The obtained results showed that the AlZn-NO-VZn complex is a shallow acceptor that can play an important role in achieving the p-type conductivity in the (Al,N) codoped ZnO films. Our results showed also that the electrical conductivity type in the (Al,N) codoped ZnO films strongly depends on the donor/acceptor concentrations ratio. The codoped ZnO films prepared under both Zn-rich and O-rich growth conditions with a donors/acceptors ratio of 1:2 have a p-type conductivity, while those prepared with a ratio of 1:1 cannot be p-type unless if they are prepared under O-rich conditions. The achieved p-type quality depends also on the used nitrogen doping source. To prepare p-type ZnO film of high quality using the (Al,N) codoping method, the use of NO or NO2 is recommended. The presence of donor defects such as oxygen vacancies and hydrogen will significantly affect the electronic properties of the (Al,N) codoped ZnO films, and if the concentration of these defects in the sample is high enough, the material can be easily converted to n-type
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