Porous silicon samples were formed on p-type silicon wafer by electrochemical method. Metal porous silicon structure was used to obtain the rectifying behavior. Current density and etching time was studied which affect the photoluminescence and energy band gap. Three different groups were prepared using different current density and varying etching time. The optical properties for p-type porous silicon were investigated by photoluminescence (PL) spectroscopy. Findings from study showed that the porous silicon has band gap energy in the range from 1.81 to 2.07 eV. The band gap energy also increased with increasing current density or increasing etching time. The PL peaks showed a steady red color shift from 500 to 800 nm with increasing etching time.
Porous silicon (PSi) layers were formed on a p-type Si wafer. Electrochemical method was used to prepare 36 samples with three values of current density (10, 20 and 30) mA/cm 2 , each involved ( 20, 40, 60 and 80) min etching times the samples were heated to three selected temperatures of 100, 200 and 350°C in three groups. The first group covers 12 samples corresponding to 10 mA/cm 2 while the other two correspond to the remaining values of current density respectively. Each annealing process for these sample groups lasted three hours in ambient air. The morphology of the layers, before and after annealing, formed by this method was investigated by Scanning Electron Microscope (SEM). Photoacoustic technique (PA) was employed carry out Thermal Diffusivity (TD) measurements. In this study, the porosity and thickness porous increased with increasing current density and etching time. While the thermal diffusivity TD increases with increasing annealing temperature.
The idea of research is the detection of gases using the transmitter and receiver system for electromagnetic radiation in the IR region using the optical absorption method. As a result of the interaction of the light with the gas molecules can be detect and measure gas pressure adoption absorption method. It was chosen best absorption band between (1.4-1.6) um at the wavelength 1.5 um to build a sensor for accurate measurement of ammonia gas which is characterized by precision, where he was the measuring pressure range (1-6) bar. The importance of the oil industry has been focusing on this kind of scientific research for the detection of ammonia gas.
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