[en] Cadmium telluride (CdTe) quantum dots (QDs) were prepared via a hydrothermal method, using 3-mercaptopropionic acid (3-MPA) as the stabilizing agent. With the help of absorption and emission spectra, it was found that prolonging the reaction time and raising the reaction temperature can increase the size of the QDs obtained, and hence induce a red shift of fluorescence emission. Rhodamine 6G was used as the reference to calculate the quantum yield (QY), and this showed that the use of extra Cd ions will distinctly increase the QY of CdTe. (paper)