Effect of the synthesis conditions on the properties of Co embedded porous Si nanostructures

Abstract

The electrodeposition of cobalt in the porous silicon (PSi) substrate was investigated in terms of the deposition times and current densities. The PSi/Co samples were characterized by SEM, XRD, Raman, and photoluminescence (PL) spectroscopies. The results indicated that for all current densities, the PL intensities of PSi/Co samples with shorter deposition times (t(s) <= 20 min) increased due to spherical Co nanoparticles (NPs) could be created the new recombination centers, compared to that of the undeposited PSi. On the other hand, the PL intensity of PSi/Co samples significantly decreased at longer deposition times (t(1) > 20 min) because of larger Co NP cluster promoted the formation of non-radiative centers. The increased PL intensities in samples with t(s) were attributed to both the quantum confinement effect and surface effects. PL analyses also suggested that after exposure to air for 60 days, PL characteristics of PSi/Co were stabilized depending on deposition time and current density.