Optical properties of CdTe/ZnTe quantum dots sandwiched between two quantum wells with ZnTe separation barriers

Temperature-dependent photoluminescence (PL) measurements were performed to investigate the optical properties of CdTeZnTe nanostructures. The activation energy of the CdTeZnTe quantum dots (QDs) sandwiched between two quantum wells (QWs) with ZnTe separation barriers, as obtained from the temperature-dependent PL spectra, was much larger than the activation energies of the QDs alone and of the QDs combined with a single QW. This behavior can be attributed to a transfer of carriers from the QWs to the QDs through a separation layer due to a nonresonant multiphonon-assisted tunneling process resulting from carrier thermal emission.