Growth and characterization of oriented cadmium sulphide nanocrystals under Langmuir-Blodgett monolayer of arachidic acid

Abstract.

Cadmium sulphide nanocrystals were grown at room temperature (20 °C) under arachidic acid monolayers floating over an aqueous solution of CdCl₂ inside an enclosed Langmuir-Blodgett set-up, through slow infusion of H₂S gas. X-ray diffraction spectra suggest an oriented growth of the crystallites. The particle sizes were found to increase with duration of exposure to the H₂S gas. Atomic force microscopy indicated that the particles were nearly circular pellets with uniform morphology throughout. In Raman spectra, the FWHM of the LO phonon was found to be large (≈20 cm^-1) for all the films grown with different exposure times in H₂S gas, and was found to reduce to 8 cm^-1 after annealing a typical sample at 500 °C for 45 min.