Preparation of porous silicon Wafers using sun light photo chemical etching (SLPCE)


porous Silicon (PS) Layers were prepared by photochemical etching using Sun Light as a Source of energy for the first time instead of industrial Sources of light Such as Lasers, Halogen and tungsten lamps. That was used to preparation (PS) by photochemical etching. Silicon Wafers n-type (100), resistivity (10Ω.cm), (40%) HF Acid, with different illumination intensities(power density) (1758, 3956, 6182 and 8902)mw /cm2 were obtained using different Lenses with different diameters (40, 60, 75 and 90) mm, focal length (13,18,41,45) cm respectively and constant etching time (60min). The morphology of the surface was studied by using an (atomic force microscope) (AFM) and (scanning electron microscope) (SEM) results shows formation of groups of pores and crystals in (nm)size with different diminution are distributed in etched area in wavy forms. The thickness of porous layers ranged from (50.06 3.68, 3.79 and 3.39) nm and the diameter of the particles are(84.06, 59.42, 51.12 and 34.8)nm respectively. The current voltage characteristics for ALthin/n-si/PS/ALthin device fabricated by sun light photochemical etching technique showed a rectifying behavior which improved with increasing light intensity.