Phonon spectra of CdS, ZnS, PbS, CuS, Ag2S, and ZnO quantum dots formed by using the Langmuir-Blodgett technology are investigated by Raman and infrared spectroscopies. The Raman spectra of structures show peaks corresponding to the scattering by longitudinal and transverse optical (LO and TO) phonons localized in quantum dots that confirm the formation of nanocrystals. In addition to TO and LO phonon modes, the modes observed in the IR spectra between the frequency positions of LO and TO phonons are attributed to the surface optical phonons in quantum dots. (C) 2010 American Vacuum Society. [DOI:10.1116/1.3442799]