Influence of beta-FeSi2 particle size and Si growth rate on 15 mu m photoluminescence from Si/beta-FeSi2-particles/Si structures grown by molecular-beam epitaxy

Si/beta-FeSi2-particles/Si structures have been fabricated by reactive deposition epitaxy for beta-FeSi2 and molecular-beam epitaxy (MBE) for Si, and the influence of the size of the beta-FeSi2 particle and the MBE-Si growth rate for embedding the beta-FeSi2 in Si on 1.5-mum photoluminescence (PL) intensity of beta-FeSi2 was investigated. The 1.5-mum PL intensity was observed to increase with the size of the beta-FeSi2 particle, but the broad background luminescence, ranging from 1.2 to 1.4 mum, also increased. Transmission electron microscopy observation suggested that the broad luminescence was due to the dislocations induced in the Si matrix when the size of the embedded beta-FeSi2 particles was too large. Furthermore, the 1.5-mum PL intensity was observed to be strongly affected by MBE-Si growth rate. This is thought to be due to the strain induced in the beta-FeSi2 particles upon being embedded in the Si. (C) 2004 American Institute of Physics