Enhancement of erbium photoluminescence by substitutional C alloying of Si

Photoluminescence (PL) at 1.54 mu m of erbium-doped Si1-yCy alloys grown by molecular beam epitaxy (MBE) has been analyzed depending on sample tempera ture, excitation density, and growth conditions. Erbium activation raises w ith increasing incorporation of substitutional carbon compared to interstit ial carbon. For [Er]=4.5x10(19) cm(-3) and y=0.1% maximum PL output at 1.54 mu m was achieved for growth temperatures at 430 degrees C. Additional ann ealing could further enhance PL intensity at 1.54 mu m. For increasing samp le temperature a decrease of PL intensity with two characteristic activatio n energies around 100 and 10-20 meV is observed, which results in quenching of PL intensity at lower temperatures for Si:Er:C layers compared to Si:Er :O layers. PL spectra show different fine structure for oxygen and carbon c odoping by MBE or ion implantation, higher efficiency, and lower PL backgro und for MBE-grown samples in contrast to ion-implanted layers. (C) 1999 Ame rican Institute of Physics. [S0003-6951(99)03043-0].