We demonstrate the dimensional tuning of InAs self-assembled quantum dots ͑QDs͒ by changing the growth kinetics during the capping of InAs islands with GaAs. Modifying the growth sequence during the capping of InAs islands, allows us to tune the thickness and lateral dimensions of the QDs while keeping the wetting layer thickness constant. Using the same method but embedding the tuned InAs islands into AlAs layers allows to further blueshift the photoluminescence emission to higher energies while keeping the wetting layer thickness constant. The main process responsible for the QDs size modification is consistent with a kinetically controlled materials redistribution of the InAs islands that minimizes the energy of the epitaxial layers at the start up of the GaAs capping deposition.
We report the quantum dot infrared photodetector using the modulation doped
InAs self-assembled
quantum dots. By modulation doping, it is possible to remove the effect of
the dopants on the energy
level in InAs dots and to attribute clearly the infrared photocurrent to the carrier excitation in InAs
dots. The infrared photocurrent in the detector was clearly observed up to
30 K. The peak energy
and the polarization dependence of the infrared photocurrent are comparable
to the infrared electron
excitation from the ground state in InAs dots to the conduction band edge of
GaAs barriers.
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