Journal of Applied Sciences and Nanotechnology

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.

Porous silicon nanoparticles, or PSNPs, are one of the most common NPS with distinct characteristics. PSNPs were created using an enhanced approach known as the electrochemical etching process. The nanoparticles were treated with a post-laser to obtain the nanoparticles, which were subsequently analyzed using (SEM), (UV-Vis), and (XRD). The size refers to porous silicon with a nanostructure. Because of the differences in interaction between the HF electrolyzed and silicon and crystal structure, PS (100) offers better NP properties than directional silicon (111). PSNPs' antioxidant activity was measured using the DPPH test, while cytotoxicity was measured using the MTT assay on Hella cells. PSNPs have an inhibitory impact on cancer cell growth and antioxidants, according to the findings. PSNPs did not have any toxicological effects on the skin, lungs, or spleen after injection.

The COVID-19 disease outbreak has emphasized the critical need for more sensitive analytical technology. Photonic technology focuses on studying light interaction analysis with the molecules to enhance diagnostic tools' accuracy. Due to the distinct spectral signatures, lasers have shown effectiveness in the classification and monitoring of viruses. This work aims to improve healthcare delivery in public areas, markets, hospitals, and airports. However, providing insights into the technical aspect also helping researchers identify the possibilities and difficulties in this field. This short review has been collect from four authoritative databases: Web of Science, Science Direct, Scopus, Google Scholar. This paper discusses emerging developments in photonic sensor applications such as telehealth, point care, and telescreens in environmental surveillance. It also includes modern studies to identify and diagnose viruses by using photonic techniques. Finally, it was found that the most effective approaches for reducing the spread of the COVID-19 virus pandemic in the environment, besides collecting the big data via an intelligent optical fibre network between the hospitals and other public places.