Carrier dynamics and activation energy of CdTe/ZnTe nanostructures with different CdTe thicknesses

We investigate the dimensional transition and optical properties of CdTe/ZnTe nanostructures with various CdTe thicknesses. The excitonic peak corresponding to the transitions from the ground electronic sub-band to the ground heavy-hole band in CdTe/ZnTe nanostructures shows different redshifts with increasing CdTe thickness due to variations in the dimensions of CdTe/ZnTe nanostructures. Time-resolved photoluminescence (PL) measurements used to study the carrier dynamics show that the decay time of 4.0 monolayer (ML) CdTe/ZnTe nanostructures is longer than that of CdTe/ZnTe nanostructures with different CdTe thicknesses. The activation energy of electrons confined in 4.0 ML CdTe/ZnTe nanostructures, as obtained from the temperature-dependent PL spectra, is higher than that of electrons confined in CdTe/ZnTe nanostructures with different CdTe thicknesses. These results indicate that the carrier dynamics and activation energy of CdTe/ZnTe nanostructures are affected by the thickness and dimensions of CdTe/ZnTe nanostructures.

► We investigate dimensional transition and optical properties of CdTe/ZnTe nanostructures with various CdTe thicknesses.
► Excitonic peak of CdTe/ZnTe nanostructures shows different redshifts with increasing CdTe thickness.
► Decay time of CdTe/ZnTe QDs is longer than those of different CdTe/ZnTe nanostructures.
► Activation energy of CdTe/ZnTe QDs is higher than those of different CdTe/ZnTe nanostructures.