Optical characterization of beta-FeSi2 layers formed by ion beam synthesis

Thin beta-FeSi2 layers have been prepared by ion beam synthesis (IBS) on (111)Si substrates. The obtained samples have been characterized by means of infrared and Raman spectroscopies. The infrared (IR) transmittance spectra show the absorption at 310 cm(-1) as an indication of the initial nucleation of beta-FeSi2 precipitates during the implantation of iron into silicon substrate. The main feature of the photoluminescence (PL) measurements at 12 K in the beta-FeSi2/(111)Si samples annealed at 850 degreesC for 90 min is an intense peak localized at 0.811 eV. This peak is assigned to optical radiative transitions intrinsic to beta-FeSi2. (C) 2004 Elsevier Ltd. All rights reserved.