The Raman spectrum of MoS2 in corundum of the Waldheim prismatine granulite shows in the high-frequency region, unusual Raman bands. Is there an explanation?
The extraordinary strong bands in the high-frequency range of the MoS2 (molybdenite from Waldheim) Raman spectrum can be traced back to surface-enhanced Raman scattering (SERS).
By etching the Königshain MoS2 surface with tetrabromoethane (TBE), it is possible to show that in the molybdenite crystals are traces of graphite (strong bands at 1336.8 and 1580.5 and 2665.0 cm-1), which are not to see in the untreated sample with the conventional Raman spectroscopy.
The surface of the treated MoS2 can be further activated by high-intense Raman treatment (532 nm, 50mW). As a result of this activation results a very strong and sharp Raman band at 873.6 cm-1.
I have obtained no answer to my question. Therefore I have looked after a possibility. The strong lines, which are reproducible, are unusual. I have seen that the SERS technique works with significant enhancement factors like 10 to a power of ten. Therefore I have today performed some experiments. And the remarkable results I have presented here in short.