The purpose of this work to study the porous silicon and fabricate optical sensor based on optimum parameters of PS, chapter one explan the history of PS, chapter two displayed the physical properties of PS and study the Electrochemical etching of porous silicon, Electrical and Photoelectrical Properties, Rapid Thermal Annealing techniques process, and Applications of Porous Silicon. chapter three explain the sample preparation and experiment methodology. chapter four was the characterization of PS using FESEM, AFM, XRD, and Photoluminescence studies before and after annealing, finally PS...