Vacuum is a technique that can be employed to measure pressures less than atmosphere (101325 mbar), the vacuum is too important in numerous fields of life. In the present research, the sensor of vacuum has been produced using a porous layer of silicon (Psi). N-type of silicon wafer (Si) has been used for formulating Psi samples utilizing photo-electrochemical etching (PECE) technique. The experimental work was carried out under different etching times (30, 60, and 90 min) while fixing the other parameters, including (24%) Hydrofluoric (HF) acid and (20 mA/cm2) current density. The pore width and depth and porosity % were confirmed using Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) tests. The tests shown a sponge-like structure of Psi and the surface roughness increased along with etching time. X-ray diffraction (XRD) verified the formation of porous silicon, the crystal size reduced, and photoluminescence (PL) elucidated that the emission peaks centered at approximately (600-625 nm) corresponding to energy bandgap (1.72-1.94 eV). The electrical properties were investigated by the electrical resistance of porous silicon with vacuum. The results evinced that the porosity, pore depth, surface roughness and the intensity of Psi increased significantly as the etching time increased, and the vacuum value was sensed by varying the electrical resistance value of the Psi after removing the air molecules from the pores, thus the resistance gradually decreased after exceeding the vacuum value 10-3 mbar.
Dawood, Noor S.; Zayer, Mehdi Q.; and Jawad, Muslim F.
"Preparation and Characteristics Study of Porous Silicon for Vacuum Sensor Application,"
Karbala International Journal of Modern Science: Vol. 8
, Article 11.
Available at: https://doi.org/10.33640/2405-609X.3209
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