VIBRATIONAL PROPERTIES OF SI GE AND A-SN/GE SUPERLATTICES WITH INTERMIXED INTERFACES/

It is found that Raman spectra of Si/Ge and alpha-Sn/Ge[001] superlatt ices are drastically modified by the introduction of interface intermi xing. Some new peaks appear due to intermixing. The calculations clear ly show that the peaks around 400 cm-1 in Si/Ge and 230 cm-1 in alpha- Sn/Ge superlattices observed in Raman experiments originate from the a lloyed layers formed at the interface. It is suggested that relative f requencies and relative intensities of some Raman peaks could be used as a measurement of the composition profiles and the degree of interfa ce perfectness.