Photoluminescence properties of ion-beam-synthesized β-FeSi2 nanocrystals in Si

We have investigated photoluminescence (PL) properties of β-FeSi2 nanocrystals in Si crystals. The PL spectrum could be separated into three major A, B and C bands and some minor bands. The B and C band (side band) spectra with a Gaussian function shape could be deduced from subtraction of the A band spectra with a Lorentzian function shape from the whole PL spectrum observed. It was found that the temperature dependence of the C band emission was quite different from that of the intrinsic band (A band) emission which follows a Varshini empirical formula. The C band emission may be originated from two competition processes which are switched at 70 K.