Applied Physics
Yasamen H. Khadim; Uday M. Nayef; Falah A-H. Mutlak
Abstract
This investigation analyzes the impact of a laser pulse energy set at 700 millijoules per pulse on silver, gold, and silver@gold nanoparticles deposited onto porous silicon (PS). Our primary objective is to discern optimal conditions by comprehensively evaluating their influence on structural, electrical, ...
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This investigation analyzes the impact of a laser pulse energy set at 700 millijoules per pulse on silver, gold, and silver@gold nanoparticles deposited onto porous silicon (PS). Our primary objective is to discern optimal conditions by comprehensively evaluating their influence on structural, electrical, morphological, and optical characteristics. Employing pulsed laser ablation in liquid, an Nd:YAG laser featuring a 10-nanosecond pulse width and a 1064 nm wavelength is utilized for nanoparticle creation. X-ray diffraction analysis (XRD) is employed to affirm the crystalline growth of core-shell nanoparticles, with distinct peaks in the data confirming the presence of both Au and Ag nanoparticles. Morphological analysis reveals a robust attachment between the nanoparticles and the porous silicon layer, indicating structural stability. The UV–vis spectra exhibit a localized surface plasmon resonance (LSPR) band within the 412–521 nm range. Notably, with an increase in gold concentration, the two peaks of the LSPR band converge into a singular peak. Comparison of the photoluminescence emission spectra of the PS substrate and NPs/PS demonstrates a significant broadening of the emission band in PS, indicative of high-quality porous silicon structure. The intriguing characteristics of Ag@Au NPs make them promising for application in gas sensor systems.
Laser Science and Technology
Sara Fadhil Abbas; Adawiya J. Hadier; Sharafaldin Al-Musawi; Bakr Ahmed Taha
Abstract
In this study, we synthesized magnesium oxide (MgO) nano flakes (NFs) through pulsed laser ablation of magnesium ribbons, investigating their potent antibacterial properties for potential biomedical applications. Thorough characterization utilizing advanced analytical techniques verified the phase purity ...
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In this study, we synthesized magnesium oxide (MgO) nano flakes (NFs) through pulsed laser ablation of magnesium ribbons, investigating their potent antibacterial properties for potential biomedical applications. Thorough characterization utilizing advanced analytical techniques verified the phase purity and functionality of the fabricated MgO NFs. Results revealed a distinctive flake-like structure with an average diameter of 100-400 nm and a slender wall thickness of 24 nm. The efficiency of the laser ablation method was validated by EDX imaging, showing high purity in the MgO sample. XRD analysis further confirmed the polycrystalline nature of MgO NFs, with dominant peaks at 2θ values of 38.86°, 59.46°, 62.83°, and 73.87° corresponding to (111), (110), (220), and (311) diffractions, respectively. UV-visible spectroscopy exhibited a broad absorption peak, and Tauc's formula yielded an energy band gap of 5.8 eV. FTIR spectroscopy detected Mg–O–Mg bending vibration, O−H stretching vibration, O=C=O stretching, and O−H bending vibration. Optimized MgO-NFs demonstrated remarkable antibacterial efficacy against both gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli) bacteria. Maximum antibacterial activity was observed at a high MgO NFs concentration (200 µg/ml), resulting in 15 mm ±0.5 mm and 16 mm ±0.5 mm inhibition zones for E. coli and S. aureus, respectively. The minimum inhibitory concentration (MIC) for both pathogens was determined to be 25 µg/ml, emphasizing the promising antimicrobial potential of the MgO NFs.
Applied Physics
Eman M. Suliman; Uday M. Nayef; Falah A. Mutlak
Abstract
In this study, Au:TiO2 nanoparticles (NPs) are prepared by using the laser ablation method in liquid at different laser energies (600, 800, and1000 mJ). After that, Au: TiO2 NPs were deposited on porous-Si(PS). Porous silicon (PS) is synthesized by using the photo-electrochemical etching (PECE) of n-type ...
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In this study, Au:TiO2 nanoparticles (NPs) are prepared by using the laser ablation method in liquid at different laser energies (600, 800, and1000 mJ). After that, Au: TiO2 NPs were deposited on porous-Si(PS). Porous silicon (PS) is synthesized by using the photo-electrochemical etching (PECE) of n-type crystalline Si (c-Si) wafers of (100) orientation. The intensity of the etching current density was (4, 12, and 20 mA/cm2), with 16% (HF), and the etching time was 15 minutes. The X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM), UV–visible spectrophotometry, and electrical properties are used to characterize the obtained particles. From the photo-detector measurements, the spectral responsivity curves three inclusive regions; the first peak was due to the absorption of UV light by Au: TiO2 NPs. The second peak was corresponding to the visible light absorption with the PS layer and the third peak was due to the absorption edge of the Si substrate. The higher responsivity of Au: TiO2 NPs/PS photo-detector was found to be 2.56A/W for specimens prepared at laser energy 800mJ.
Nanotechnology
Israa F. Hasan; Khawla S. Khashan; Aseel A. Hadi
Abstract
Titanium dioxide nanoparticles were produced in this work by laser ablation of a high purity titanium objective immersed in distilled water. Optical and structural properties of the obtained TiO2 NPs using a Q-switched Nd: YAG laser of 1064nm wavelength with different laser energy (80, 100, 120, 140, ...
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Titanium dioxide nanoparticles were produced in this work by laser ablation of a high purity titanium objective immersed in distilled water. Optical and structural properties of the obtained TiO2 NPs using a Q-switched Nd: YAG laser of 1064nm wavelength with different laser energy (80, 100, 120, 140, and 160) mJ at 100 pulses was studied. The produced TiO2 NPs were characterized employing UV-VIS Spectrophotometer, X-ray diffraction, and scanning electron microscopy (SEM). The obtained TiO2NPs showed a decrease in transmittance in the region of the UV spectrum and an increase in the visible spectrum region. The estimated optical band gap of the TiO2NPs was 3.89eV, 3.8eV, and 3.70eV at 80, 120 and 160mJ laser energy, respectively. The as-produced TiO2NPs appear to be a Brookite crystalline phase with the preferential orientation along (200) direction. The scanning electron microscopy assays showed that the TiO2 NPs have a cauliflower shape. Results show that with increasing the energy of laser pulse, the size of nanoparticles was increased noticeably. Where the particle size and its morphology are affected by laser energy.