Electron-filling modulation reflectance in charged self-assembled InxGa1-xAs quantum dots

We present some observations of electron-filling modulation reflectance in charged self-assembled InxGa1 - xAs quantum dots. This electron-filling mod ulation reflectance is a different type of electroreflectance, which is bas ed on the Pauli blocking of interband transitions in quantum dots. By adjus ting the appropriate ac and de reverse biases, electron filling in the quan tum dots can be modulated. Experimentally determined interband transitions have been compared with those obtained from photoluminescence spectra. The good agreement between these results reveals that at least three quantum-co nfined electron states are contained in our quantum dots due to their elect ron-filling character. As the temperature is increased, the relative intens ity of each state can directly reflect the electron populations of the quan tum states. The technique developed here provides an efficient way to obser ve the interband transitions of quantum dots. [S0163-1829(99)51028-X].