Nanowire based size-dependent Photoluminescence and Raman studies of N type porous silicon etched under illumination of varying wavelengths

A comparative study of N type porous silicon (PS) morphology by using Field Emission Scanning Electron Microscope (FESEM) Imaging, Raman Spectroscopy and Photoluminescence (PL) spectroscopy analysis. Samples of crystalline silicon were electrochemically etched at a constant current density and a constant anodization time illuminated under different wavelengths of visible light emitted by LEDs to convert them into nanowire-based PS wafers. FESEM characterization showed formation of nanowires of different porosities on the wafer for varying wavelengths subjected to the samples during etching. Raman spectroscopy further showed right shift in Raman peaks of the amorphous silicon wafer while PL spectroscopy concluded in tuning of energy band gap of the samples illuminated under different wavelengths of light. In this work, we show the differences obtained in the behavior of PS when etched under different degrees of illumination for further application in fabrication of integrated silicon-based optoelectronic systems as the properties of a porous silicon such as porosity, pore diameter and thickness depend heavily on the fabrication process and can be comfortably controlled.