  We report crystal growth and Raman spectroscopy characterization of pure and
mixed bulk topological insulators. The series comprises of both binary and
ternary tetradymite topological insulators. We analyzed in detail the Raman
peaks of vibrational modes as out of plane Ag, and in plane Eg for both binary
and ternary tetradymite topological insulators. Both out of plane Ag exhibit
obvious atomic size dependent peak shifts and the effect is much lesser for the
former than the latter. The situation is rather interesting for in plane Eg,
which not only shows the shift but rather a broader hump like structure. The de
convolution of the same show two clear peaks, which are understood in terms of
the presence of separate in plane BiSe and BiTe modes in mixed tetradymite
topological insulators. Summarily, various Raman modes of well-characterized
pure and mixed topological insulator single crystals are reported and discussed
in this article.
