| Abstract: | Topography and electrical properties of InAs quantum dots Self assembled InAs‐islands were grown on GaAs with molecular beam epitaxy in the Stranski‐Krastanow growth mode. The topography of surface quantum dots was investigated by atomic force (AFM) and scanning electron microscopy (SEM). While the AFM enables to determine the dot height of ≈ 10 nm the SEM is best suited to study the lateral dimensions of uncapped islands. The latter technique gives a dot diameter of ≈ 30 nm. Although the size distribution of the islands is convoluted in the capacitance measurements on a dot ensemble, it was possible to determine roughly a Coulomb blockade energy of ≈ 20 meV for the ground state and ≈ 10 meV for the first excited dot level. Taking advantage of AFM‐lithography we were able to study electron transport through a single InAs island. Here we got a Coulomb blockade energy of 12 meV when electrons tunnel through the first excited state of the dot. |
