Enhanced photoluminescence from Si~+ and C~+ ions co-implanted porous silicon formed by electrochemical anodization

摘要

Enhanced photoluminescence (PL) was obtained from electrochemically formed porous silicon (PS) on crystalline silicon wafer with co- implantation of Si~+ and C~+ ions. It is demonstrated that PS formation can preferentially be initiated during electrochemical anodization process for ion implanted samples, as shown from the scanning electron microscopy (SEM) characterization and current density versus etching duration (J-t) plots during anodization process. For the PS sample with co-implantation of Si~+ and C~+ ions, SiC (or amorphous Si_(1-x)C_x) nanostructures are embedded in the SiO_2 matrix after high-temperature annealing, as indicated from X-ray Photoelectron spectroscopy (XPS) characterization. The enhanced photoluminescence (PL) emission from the PS sample with co-implantation of Si~+ and C~+ ions is attributed to the enhanced formation of PS induced by ion implantation. Meanwhile, the appearing of SiC (or amorphous Si_(1-x)C_x) nanostructures with localized recombination of optically excited holes and electrons in the SiO_2 matrix, also contributes to the enhanced PL emission. Porous silicon with co-implantation of Si~+ and C~+ ions shows promising perspective for applications in Si-based optoelectronics.