Abstract
CdTe and ternary CdZnTe quantum dots capped with 3-mercaptopropionic acid in aqueous medium with different percentages of Zn have been prepared using K2TeO3 as a source of tellurium. The structure and morphology of these quantum dots were characterized by XRD, TEM, EDX, FTIR and Raman spectroscopy. The results revealed that the ternary CdZnTe quantum dots (QDs) have nearly spherical shape with hexagonal structure. Doping with Zn leads to a pronounced change in relative intensity of the X-ray diffraction peaks. The optical properties were investigated by using UV-Vis absorption and photoluminescence measurements. The UV-Vis showed a gradual increase in the optical band gap of ternary alloy compound of CdZnTe QDs plus a continuous shift of photoluminescence emission with increasing of Zn content. The color distribution analysis showed a gradual change in color with Zn percentage for red, green and blue components. The nanoparticle sizes were determined from optical absorption, XRD, Raman and HRTEM measurements indicating that the prepared binary CdTe and ternary CdZnTe capped with MPA are in a strong confinement regime as an indicative of quantum dots structure.