Widely tunable intersubband energy spacing of self-assembled InAs/GaAs quantum dots due to interface intermixing

In this article, we showed the significant reduction of the energy spacing between ground state and excited state emissions from InAs/GaAs quantum dot s (QDs) due to interface interdiffusion induced by thermal treatment. In ad dition, the strong narrowing of the luminescence linewidth of the ground st ate and excited state emissions from the InAs dot layers for the annealed s amples indicates an improvement of the size distribution of the QDs. Large blueshift of the energy positions of both emissions was also observed. High resolution x-ray diffraction experiments give strong evidence of the inter face atom interdiffusion in the annealed samples. This work shows the abili ty to tune the wavelength for applications like infrared detectors and lase rs based on intrasubband transitions of self-assembled QDs. (C) 1999 Americ an Institute of Physics. [S0021-8979(99)05017-3].