Regular Article
Applied Physics
Ausama I. Khudiar
Abstract
This study investigates the effects of pulsed Nd:YAG laser annealing at a wavelength of 532 nm on the photoconductivity properties of cadmium sulfide (CdS) thin films prepared by thermal evaporation. In addition, measurements at room temperature showed an ohmic behavior in the voltage-current characteristics ...
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This study investigates the effects of pulsed Nd:YAG laser annealing at a wavelength of 532 nm on the photoconductivity properties of cadmium sulfide (CdS) thin films prepared by thermal evaporation. In addition, measurements at room temperature showed an ohmic behavior in the voltage-current characteristics of the CdS thin films. It was observed that after laser irradiation, the photosensitivity of the film increased due to the improved crystallinity and decreased defect density of the thin films, as shown by the increase in the ratio of light to dark current (Iph/Id) from 0.35 to 0.42. The photocurrent also follows the relationship (Iph∝FγI), with γ-values of 1.037 and 1.047 after annealing due to monomolecular recombination, reduced grain boundaries and enhanced recrystallization. The spectral response peaked at 585 nm, which corresponds to the optical band gap of the CdS thin film. The transient photoconductivity, which describes the time-dependent change in the electrical conductivity of the material when exposed to light, was measured and showed significantly increased decay rates. The differential lifetime (τd) decreased from (90.8 sec) to (39.2 sec) after Nd:YAG laser annealing, which can be attributed to a lower density of defect states and an improvement in film quality. The results highlight the ability of Nd:YAG laser annealing to maximize the photonic and electronic properties of CdS thin films through structural and carrier recombination dynamics, increasing their use in optoelectronic devices.
Regular Article
Biotechnology
Fattin A. Fadhil; Azhar M. Haleem; Abdulrahman Khalaf Ali; Ahlam T. Mohammed
Abstract
New approaches have been developed to combat bacterial infections because of the growing threat of antibiotic-resistant bacteria. Gold colloidal nanoparticles and their applications as antibacterial agents have shown promising strategies due to these properties. The properties of nanoparticles, including ...
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New approaches have been developed to combat bacterial infections because of the growing threat of antibiotic-resistant bacteria. Gold colloidal nanoparticles and their applications as antibacterial agents have shown promising strategies due to these properties. The properties of nanoparticles, including size, shape, and surface charge, play an essential role in determining antibacterial activity. Pulsed laser ablation in a liquid medium was utilized to produce gold nanoparticles, an environmentally friendly method. Gold NPs were produced in ultrapure water. Experimental research was done to determine the impact of the number of laser pulses on the nanoparticles' size, shape, and concentration. Surface plasmon resonance (SPR) peaks for gold nanoparticles were detected by UV–visible spectroscopy at approximately 525 nm in the visible region. Transmission electron microscopy (TEM) showed the appearance of spherical nanoparticles with an average size of 20 to 80 nm. For gold nanoparticles, increasing laser pulses from 100 to 250 pulses while maintaining the fixed energy of the laser at 600 mJ reduced the average nanoparticle size. S. mutans were isolated to study and evaluate the antibacterial effects of AuNP substances using the suitable diffusion method. The antibacterial examination revealed valuable results for gold nanoparticles, which showed a more significant effect on bacteria at high concentrations. The best results were found for the sample prepared at the highest concentration at 250 pulses. Toxicity assessments of the materials revealed low toxicity levels of this material, confirming their safety for human use.
