We investigate the effects of the capping layer thickness on the optical properties of CdTe/ZnTe quantum dots (QDs). The time-resolved photoluminescence (PL) measurements used to study the carrier dynamics show a shorter decay time for CdTe/ZnTe QDs with decreasing thickness of the ZnTe cap layer due to an increase in the nonradiative surface recombination rate. The activation energy of the electrons confined in the CdTe/ZnTe QDs, as obtained from the temperature-dependent PL spectra, decreases with the thickness of the ZnTe cap layer. These results indicate that the carrier dynamics and activation energy of CdTe/ZnTe QDs are affected by the thickness of the ZnTe cap layer. (C) 2012 Elsevier B. V. All rights reserved.