Observation of interdot energy transfer between InAs quantum dots

We observed interdot excitation energy transfer between vertically aligned InAs quantum dots (QDs) separated by a 24-nm-thick spacer layer. This transfer was explained by resonant energy transfer via an optical near-field interaction between the first excited state of small QDs and the second excited states of large QDs. The excitation intensity dependence of the photoluminescence intensities showed that the energy transfer times were 75ps at 15K and 4ns at 77K. Our experimental results indicated that the III-V compound semiconductor QDs are appropriate for nanophotonic switching devices.