Fine Structure of photoluminescence spectra from Erbium incorporated with Iron in oxidised porous silicon

We report 77 K Photoluminescence (PL) and Photoluminescence Excitation (PLE) spectroscopies of Er ions incorporated with Fe in oxidized porous silicon (OPS) in the form of 5–50 nm sized clusters containing Fe, O, and Er. Twenty sharp (FWHM of about 0.4 meV) PL s peaks related to the transitions between highly split levels of 4I13/2 and 4I15/2 multiplets were observed. Two different Er centers having cubic and lower than cubic symmetries were identified. The photoluminescence excitation spectrum of the 1533 nm PL peak comprises no resonant features but a broad band spanning from 300 to 570 nm. The mechanism of excitation of Er ions through Fe : O : Er nanoclusters in the OPS host is presented.