Photoresponse of porous silicon for potential optical sensing

In this work, porous silicon (P-Si) structures were fabricated by anodizing n-type monocrystalline Si into an ethanoic-HF solution. Anisotropic electrochemical etching with constant time and current density was carried out to fabricate pores and their average diameter was found to be ∼700 nm. Raman spectra exhibited widened peaks for red, blue, and green wavelengths. The widened photoluminescence (PL) spectrum was blue-shifted owing to the quantum confinement effect. The P-Si exhibited an energy gap of 1.80 eV and manifested a direct bandgap. The photoresponse of the fabricated P-Si based device was studied at different laser irradiation wavelengthsin the range of 400–1100 nm. The best photoresponse was observed for 785 nm wavelength and the corresponding sensitivity was determined to be 9.4%. Hence, the P-Si can potentially be used for visible range photodetectors.