We have studied the growth of self-assembled CdTe/ZnTe quantum dots (QDs) on both GaAs (100) and Si (100) substrates. The growth of self-assembled CdTe/ZnTe QDs on substrates shows many difficulties which are not completely solved yet. In contrast, on GaAs substrates, good crystalline quality is obtained. The results of the atomic force microscopy images showed that CdTe/ZnTe QDs were formed on GaAs (100) and Si (100) substrates. The activation energy of the electrons confined in the CdTe/ZnTe QDs grown on GaAs (100) and Si (100) substrates was obtained from the temperature-dependent photoluminescence spectra.