A potential optical sensor based on nanostructured silicon

Silicon (Si); the most abundant raw material on the earth’s crust upholds a promising future in the silicon or electronic industry. However, the intrinsic indirect bandgap (1.12 eV), limits its usage in optoelectronics devices due to the passage of the infrared spectrum. Herein, we have structurally modified the Si structure into a nanostructured material like porous silicon (PS) for application in optoelectronic devices. In order to make PS structures, n-type monocrystalline Si was anodized in an ethanoic-HF solution. The average diameter of the pores created by anisotropic electrochemical etching with fixed time and current density was determined to be around 250 nm. The PS demonstrated a direct bandgap and an energy gap of 1.73 eV. The obtained PS-based device’s photoresponse was investigated at various laser irradiation wavelengths. The best response sensitivity of 11.18% was noted at a wavelength of 786 nm, thus, promising to be a potential material for visible range photodetectors.