Applied Physics
Salah M. Abdul Aziz; Uday Muhsin Nayef; Mohammed Soham Rasheed
Abstract
Zinc oxide nanoparticles (ZnO NPs), copper oxide nanoparticles (CuO NPs) and CuO@ZnO NPs as a colloidal core-shell solution were synthesized by laser ablation. A Nd:YAG laser with an energy of 700 mJ, a wavelength of 1064 nm and 200 pulses was used for the ablation process. The colloidal solution was ...
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Zinc oxide nanoparticles (ZnO NPs), copper oxide nanoparticles (CuO NPs) and CuO@ZnO NPs as a colloidal core-shell solution were synthesized by laser ablation. A Nd:YAG laser with an energy of 700 mJ, a wavelength of 1064 nm and 200 pulses was used for the ablation process. The colloidal solution was deposited on porous silicon (PSi) using the drop-casting method. The PSi substrates were prepared by photoelectrochemical etching (PECE) on n-type (111) silicon wafers. The study investigated the influence on the electrical, optical, morphological and structural properties of the CuO NPs and ZnO NPs samples when they were converted into a core-shell, specifically for their use in photodetector applications. XRD analysis revealed the presence of CuO, ZnO and CuO@ZnO by diffraction peaks at different angles. According to the SEM images, the nanoparticles show randomly distributed spherical grains, while PSi exhibits a sponge-like structure. The core-shell shape is confirmed by TEM images, which show a dark inner region consisting of CuO NPs and a much lighter outer region consisting of the ZnO nanoshell. The optical properties of the CuO@ZnO NPs were investigated and a minimum energy gap of 2.8 eV was found. The CuO@ZnO NPs/PSi/n-Si photodetector showed improved current-voltage (J-V) characteristics, rectifying properties and remarkable sensitivity in the visible to near-infrared region compared to other photodetector samples. The fabricated photodetector confirmed improved quantum performance, especially in the visible spectrum. The work aims to synthesize CuO@ZnO core-shell nanoparticles by a laser ablation technique to improve the electrical properties and spectral response of photodetectors.
Applied Physics
Yasamen H. Khadim; Uday M. Nayef; Falah A-H. Mutlak
Abstract
This study analyzes the effects of laser pulse energy set at 700 millijoules per pulse on silver, gold and silver@gold nanoparticles deposited on porous silicon (PS). Our main goal is to determine the optimal conditions by comprehensively evaluating their influence on structural, electrical, morphological ...
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This study analyzes the effects of laser pulse energy set at 700 millijoules per pulse on silver, gold and silver@gold nanoparticles deposited on porous silicon (PS). Our main goal is to determine the optimal conditions by comprehensively evaluating their influence on structural, electrical, morphological and optical properties. In pulsed laser ablation in liquid, a Nd:YAG laser with a pulse width of 10 nanoseconds and a wavelength of 1064 nm is used to produce the nanoparticles. X-ray diffraction (XRD) analysis confirms the crystalline growth of the core-shell nanoparticles with distinct peaks in the data confirming the presence of both Au and Ag nanoparticles. Morphological analysis shows a robust connection between the nanoparticles and the porous silicon layer, indicating structural stability. The UV–vis spectra show a localized surface plasmon resonance band (LSPR) in the range of 412–521 nm. It is noticeable that with increasing gold concentration the two peaks of the LSPR band converge to a single peak. Comparison of the photoluminescence emission spectra of the PS substrate and the NPs/PS shows a clear broadening of the emission band in PS, indicating a high-quality porous silicon structure. The intriguing properties of Ag@Au NPs make them promising for application in gas sensing systems.
