A Ph.D. thesis titled  Fabrication and Characterization of silicon nanowires heterojunction for Photonic Devices was defended at the College of Science, Department of Physics on )May 15, 2023 ), for the Ph.D. Candidate  Hana H.Inaya. The thesis aims to to silicon nanowires (SiNWs) arrays were prepared by the metal-assisted chemical etching (MACE) method using an Ag as a catalyst  , Structural, morphological, and optical properties of prepared SiNWs are investigated,were application in the heterojunction solar cells, photosensor,and as working electrodes in the photoelectrochemical cell.