The low-temperature (2K) photoluminescence properties of Si1-xGex and Si1-x-yGexCy epitaxial layers on Si, where x was equal to 0.13 and y was equal to 0.014 at peak concentration, were investigated after ion-beam synthesis. The samples were prepared with or without C-ion implantation at room temperature, and by using 3 subsequent crystallization techniques: furnace annealing at up to 840C, ion beam-induced epitaxial crystallization (using 400keV Ge or Ar ions at 300 to 350C), and ion beam-induced epitaxial crystallization followed by furnace annealing at up to 640C. It was found that, although furnace-annealed Si1-x-yGexCy samples exhibited G-line (Cs-Sii-Cs complex) emissions at 0.969eV, ion beam-induced epitaxial crystallization-grown samples exhibited a sharp non-phonon emission at 1.0193eV. This indicated that C-atom agglomeration predominated in furnace annealing-grown samples, while the creation of trigonal tetra-vacancy clusters predominated in ion beam-induced epitaxial crystallization-grown samples. On the other band, ion beam-induced epitaxial crystallization grown Si1-x-yGexCy samples (with Ge ions and furnace annealing) exhibited neither G-line emissions; thus indicating that good crystalline Si1-x-yGexCy layers without C agglomeration were formed by using this technique. On the other hand, ion beam-induced epitaxial crystallization-grown samples (with Ar ions and furnace annealing) exhibited novel successive photoluminescence vibronic side-bands at 0.98 to 1.03eV. On the basis of the excitation power dependences, they were deduced to be associated with excitons which were bound to defect levels that were created by Ar+ bombardment.

H.Katsumata, N.Kobayashi, Y.Makita, M.Hasegawa, N.Hayashi, H.Shibata, S.Uekusa: Nuclear Instruments and Methods in Physics Research B, 1997, 121[1-4], 146-50