Preparation and Characterization of Porous Silicon for Photodetector Applications

Photoelectrochemical etching (PECE) was used to prepare porous silicon (PS) layers of polished surfaces of (100) n-type silicon wafers with a resistance of 0.1-100 μm and thickness of 600 ± 25 μm. The directed slices are to be catalyzed at different etching times (5, 15, 25 min) with a constant Hydrofluoric acid of 20% and with a fixed current density of 20 mA/cm². The porous silicon morphology was investigated using scanning electron microscopy (SEM). Samples were formed by different engraving times. It revealed that the silicon surface has a layer of sponge-like structure, with the average pore diameter (740±1 nm, 550±2 nm,460±3 nm) of the porous silicon increasing as the etching time increased. PS Al PS /Si /Al photodetectors were found to work as a photodetector over a wide wavelength responsivity.