Raman studies in CdS thin films in the evolution from cubic to hexagonal phase

Evolution of optical phonons in CdS nanowires, nanobelts, and nanosheets

“…10, 19 Here, we observe the 1LO phonon energy increases systematically by ϳ6 cm from a single NW ͑ϳ200 nm diameter͒ to a single NB ͑ϳ1.3 m width͒ and to a single NS ͑ϳ3.4 m width͒, suggesting that the lattice contracts as the lateral size increases. The strain associated with a lattice contraction of ⌬c / c can be calculated using the following equation; ⌬ / 0 = ͑1+3⌬c / c͒ −␥ − 1, where ⌬ is the 1LO phonon energy shift from its bulk value 0 and ␥ is the Grüneisen parameter ͑1.1 for CdS͒.…”

Hydrostatic pressure effect on the optical spectra of glass-embedded CdS1-xSexnanocrystals

“…The Raman line intensities in NCs are subject to resonance effects and, hence, cannot be used for quantitative estimates. If the presence of NCs with zinc-blende cubic structure is assumed, it will be also difficult to confirm its coexistence with wurtzite since the LO phonon frequencies for the two phases are very close to each other [25], and in NCs for both of them the effects of phonon confinement and surface phonons on the Raman band frequencies are larger than the difference between the phonon frequencies for the two phases [26]. Therefore, Raman spectroscopy cannot be applied to confirm the phase coexistence in this particular case.…”

Extra Raman modes in CdS during cubic to hexagonal structural transformation

“…In a previous work paper, 9 we reported a blue shift of the E 1 (TO) phonon due to the ZB ! W structural phase transition.…”