Enhancement of porous silicon photoluminescence by electroless deposition of nickel

Nickel-porous silicon nanocomposites (PS/Ni) are elaborated by an electroless deposition method using NiCl₂ aqueous solution. The presence of nickel ions in the porous layer is confirmed by Fourier Transformed InfraRed spectroscopy (FTIR) and Raman spectroscopy. The photoluminescence (PL) spectra of PS/Ni, prepared at different electroless durations (t_edp), are analyzed. A remarkable enhancement in the integrated PL intensity of PS containing nickel was observed. The lower t_edp favor the deposition of nickel in PS, hence the silicon dangling bonds at the porous surface are quenched and this was increased the PL intensity. However, for the longer t_edp, the PL intensity has been considerably decreased due to the destruction of some Si nanocrystallites. The PL spectra of PS/Ni, for t_edp less than 8 min, show a multiband profile indicating the creation of new luminescent centers by Ni elements which induces a strong modification in the emission mechanisms. - Highlights: • Deposition of Ni ions into porous silicon (PS) layer using the electroless method. • Formation of Ni–O bonds on the porous layer. • The photoluminescence (PL) intensity of PS is enhanced after Ni deposition. • The increase of the PL is due to the contribution of radiative centers related to Ni