Laser Science and Technology
Intisar A. Naseef; Alwan M. Alwan; Mehdi Q. Zayer; Layla A. Wali
Abstract
In scientific research, the search for cost-efficient and scalable functional materials for substantial and practical applications is necessary. Therefore, metallic materials at the nanoscale represent a rapidly growing area of research, especially as plasmonic materials in the field of surface-enhanced ...
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In scientific research, the search for cost-efficient and scalable functional materials for substantial and practical applications is necessary. Therefore, metallic materials at the nanoscale represent a rapidly growing area of research, especially as plasmonic materials in the field of surface-enhanced Raman scattering (SERS). In this study, the potential of copper nanowires (CuNWs) and palladium nanoparticles (PdNPs) as thin films on the porous silicon (PS) surface was investigated and compared. Their parameters as plasmonic SERS sensing materials were investigated by detecting sodium nitrite (NaNO2) molecules as the analyzing material. CuNWs and PdNPs were locally deposited on the PS substrate by the immersion method to synthesize Cu/PS and Pd/PS SERS sensors. The successful fabrication of these sensors was confirmed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), and Raman measurements. The results show that the nanostructures of the metallic thin films are evenly distributed on the PS surface and that hot spot areas have formed in between. The Raman peaks of NaNO2 were effectively detected even at extremely low concentration values. Therefore, CuNWs and PdNPs were integrated with PS in the SERS to improve the detection process. Excellent detection of (5×10-6) M NaNO2 concentration was achieved with the Cu/PS and Pd/PS SERS sensors with high amplification factors of (0.43×108) and (0.11×108), respectively.
Laser Science and Technology
Noor S. Dawood; Mehdi Q. Zayer; Muslim F. Jawad
Abstract
The manufacturing of vacuum sensors is critical to several vacuum-based applications. Porous silicon (PSi) was chosen as the vacuum sensor due to the possibility of moving air particles settled inside the pores while being put in the vacuum. The characteristics of porous silicon sensing to the evacuation ...
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The manufacturing of vacuum sensors is critical to several vacuum-based applications. Porous silicon (PSi) was chosen as the vacuum sensor due to the possibility of moving air particles settled inside the pores while being put in the vacuum. The characteristics of porous silicon sensing to the evacuation of gases during vacuum was inferred by changing in the electrical resistivity. This work depends on the change in the electrical resistance of the PSi layers that was prepared via photo-electrochemical technique on the n-type (100) oriented silicon wafer. The surface topography of porous silicon is necessary to understand the morphological properties. Therefore, structural and morphological characterization of PSi samples were studied and analyzed using the scanning electron microscope (SEM) and X-Ray Diffraction (XRD) pattern. The etching process was carried out with various etching times, hydrofluoric acid (HF) concentration, and constant current density. The results showed that the pore size is increased as the etching time increased. The etching time produced pores of different sizes. The electrical resistance values were calculated after placing the sample in the vacuum system, starting from atmospheric pressure down to torr. The electrical properties of PSi indicate that electrical resistance gradually decreases with increasing vacuum pressure.
Nanotechnology
Duha S. Hassan; Mehdi Zayer
Abstract
The polycrystalline thin films were deposited on glass substrate at room temperature by pulsed laser deposition PLD technique. The effects of annealing treatment by used the Oil Thermal Annealing (OTA) process on the structural, optical and electrical properties of ZnO thin film films were investigated. ...
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The polycrystalline thin films were deposited on glass substrate at room temperature by pulsed laser deposition PLD technique. The effects of annealing treatment by used the Oil Thermal Annealing (OTA) process on the structural, optical and electrical properties of ZnO thin film films were investigated. The film structure was investigated by X-ray diffraction to indicate that the heat treatment after the OTA process gives the optimized condition of crystalline. The transmission spectrum of the film was measured by UV-V is spectrophotometer, and the Urbach energy and forbidden band width were calculated. The surface topography of the film was observed by scanning electron microscopy (SEM) image of the ZnO thin film at the OTA process shows the changes in the shape and size of the grains. The atomic force microscopy (AFM) effect of heat treatment was demonstrated by the change in the surface roughness of the ZnO thin film. The electrical properties of thin film were optioned by Hall Effect technique. That these improvements in the ZnO thin film physical properties were annealing temperatures by OTA at 150 °C, 200 °C, 250 °C and 300 °C.
