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.
Nanotechnology
Shahad S. Khudiar; Uday M. Nayef; Falah A. Mutlak
Abstract
Photoelectrochemical etching (PECE) was used to prepare porous silicon (PS) layers of polished surfaces of (100) n-type silicon wafers with a resistance of 0.1-100 μm and thickness of 600 ± 25 μm. The directed slices are to be catalyzed at different etching times (5, 15, 25 min) with a constant ...
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Photoelectrochemical etching (PECE) was used to prepare porous silicon (PS) layers of polished surfaces of (100) n-type silicon wafers with a resistance of 0.1-100 μm and thickness of 600 ± 25 μm. The directed slices are to be catalyzed at different etching times (5, 15, 25 min) with a constant Hydrofluoric acid of 20% and with a fixed current density of 20 mA/cm². The porous silicon morphology was investigated using scanning electron microscopy (SEM). Samples were formed by different engraving times. It revealed that the silicon surface has a layer of sponge-like structure, with the average pore diameter (740±1 nm, 550±2 nm,460±3 nm) of the porous silicon increasing as the etching time increased. PS Al PS /Si /Al photodetectors were found to work as a photodetector over a wide wavelength responsivity.
