  We have grown thulium tellurides (TmTe2, TmTe3) thin layers (less than four
layers) on graphene/SiC (0001) by molecular beam epitaxy. The charge density
waves (CDWs) and lattice superstructures (LSs) are investigated by scanning
tunneling microscopy. Clear CDW patterns in real space are observed on surface
of metallic TmTe3. Two CDWs are with wave vectors 0.29c* and 0.31a*
respectively. LSs with various periods are unveiled on the surface of TmTe2 and
TmTe3. The electronic structures of these films are semiconducting. These
results show that superstructures in rare earth tellurides can have two
origins, CDWs or LSs.
