  A number of the charge-density-wave materials reveal a transition to the
macroscopic quantum state around 200 K. We used graphene-like mechanical
exfoliation of titanium diselenide crystals to prepare a set of films with
different thicknesses. The transition temperature to the charge-density-wave
state was determined via modification of Raman spectra of titanium diselenide
films. It was established that the transition temperature can increase from its
bulk value to ~240 K as the thickness of the van-der-Waals films reduces to the
nanometer range. The obtained results are important for the proposed
applications of such materials in the collective-state information processing,
which require room-temperature operation.
