Salem Omar Elhamali

@asmarya.edu.ly

Electrical and Electronic Engineering Department, Faculty of Engineering,
Alasmarya Islamic University

Salem Omar Elhamali


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https://researchid.co/salemomar

RESEARCH, TEACHING, or OTHER INTERESTS

Electrical and Electronic Engineering
3

Scopus Publications

Scopus Publications

  • Defect engineering and dopant activation of room temperature grown aluminium-doped zinc oxide thin films
    Salem O. Elhamali, Nikolaos Pliatsikas, James A. Hillier, Wayne M. Cranton, X. Hou, Nikolaos Kalfagiannis, Panos Patsalas, Demosthenes C. Koutsogeorgis
    Applied Surface Science Advances, 2025
    The impact of structural defects on the electrical properties of aluminium doped zinc oxide (AZO) thin films is investigated by varying sputter deposition and post deposition annealing conditions. Results demonstrate sputtered species of high kinetic energy at high radio frequency power (or low sputtering pressure) facilitate the production of AZO films with enhanced crystallinity, grain growth, and compactness with reduced trap defects at grain boundaries. A resistivity of 1.11 × 10 –3 Ω.cm is achieved for the optimised as-deposited samples at room temperature (RT), using 3.95 W/cm 2 sputtering at 2 mTorr of Ar. Post deposition annealing via pulsed Krypton Fluoride (KrF λ = 248 nm) excimer laser annealing (ELA) and rapid thermal annealing (RTA), provided a functional means to further manipulate the defects in terms of density and distribution. ELA (5 pulses at 125 mJ/cm 2 in air) and RTA (300 °C/20 s in nitrogen) resulted in a ∼50 % resistivity reduction to ∼5.20 × 10 –4 Ω.cm due to an increase of both free electron density and Hall mobility. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and Hall Effect measurements demonstrated a reduction of structural, adsorbed, and morphological defects, with an enhancement of compactness and the effective incorporation of Al into the ZnO lattice. ELA increased the visible transparency from 82 % to 86 %, and the bandgap ( Eg ) from 3.69 eV to 3.80 eV. RTA also increased the bandgap to 3.80 eV, with a slightly larger increase in the visible transparency to 88 %. The optimised ELA and RTA procedures present a roadmap of rapid annealing conditions following low temperature deposition suitable for the optoelectronics industry and transparent electrodes applications.
  • Enhanced electrical and optical properties of room temperature deposited Aluminium doped Zinc Oxide (AZO) thin films by excimer laser annealing
    S.O. El hamali, W.M. Cranton, N. Kalfagiannis, X. Hou, R. Ranson, D.C. Koutsogeorgis
    Optics and Lasers in Engineering, 2016
    High quality transparent conductive oxides (TCOs) often require a high thermal budget fabrication process. In this study, Excimer Laser Annealing (ELA) at a wavelength of 248 nm has been explored as a processing mechanism to facilitate low thermal budget fabrication of high quality aluminium doped zinc oxide (AZO) thin films. 180 nm thick AZO films were prepared by radio frequency magnetron sputtering at room temperature on fused silica substrates. The effects of the applied RF power and the sputtering pressure on the outcome of ELA at different laser energy densities and number of pulses have been investigated. AZO films deposited with no intentional heating at 180 W, and at 2 mTorr of 0.2% oxygen in argon were selected as the optimum as-deposited films in this work, with a resistivity of 1×10−3 Ω.cm, and an average visible transmission of 85%. ELA was found to result in noticeably reduced resistivity of 5×10−4 Ω.cm, and enhancing the average visible transmission to 90% when AZO is processed with 5 pulses at 125 mJ/cm2. Therefore, the combination of RF magnetron sputtering and ELA, both low thermal budget and scalable techniques, can provide a viable fabrication route of high quality AZO films for use as transparent electrodes.
  • An alternative non-vacuum and low cost ESAVD method for the deposition of Cu(In,Ga)Se2 absorber layers
    Mingqing Wang, Xianghui Hou, Junpeng Liu, KwangLeong Choy, Paul Gibson, Elhamali Salem, Demosthenes Koutsogeorgis, Wayne Cranton
    Physica Status Solidi A Applications and Materials Science, 2015
    In this article, an environmentally friendly and non-vacuum electrostatic spray assisted vapor deposition (ESAVD) process has been developed as an alternative and low cost method to deposit CIGS absorber layers. ESAVD is a non-vacuum chemical vapor deposition based process whereby a mixture of chemical precursors is atomized to form aerosol. The aerosol is charged and directed towards a heated substrate where it would undergo decomposition and chemical reaction to deposit a stable solid film onto the substrate. A sol containing copper, indium, and gallium salts, as well as thiourea was formulated into a homogeneous chemical precursor mixture for the deposition of CIGS films. After selenization, both XRD and Raman results show the presence of the characteristic peaks of CIGSSe in the fabricated thin films. From SEM images and XRF results, it can be seen that the deposited absorbers are promising for good performance solar cells. The fabricated solar cell with a typical structure of glass/Mo/CIGSSe/CdS/i-ZnO/ITO shows efficiency of 2.82% under 100 mW cm−2 AM1.5 illumination.