Multiple gated InAs dot ensembles

We adapt a multiple gating technology to characterize electrically an ensem ble of "self-assembled" InAs dots embedded in a plane within an Al0.20Ga0.8 0As tunneling barrier. Although the mu m-sized mesa incorporates several hu ndred dots, we find that only a few of them contribute to the current close to threshold. Gating allows us to probe the origin of the sharp current pe aks, and we can classify these peaks into families in a simple way accordin g to their gate voltage dependence. (C) 1999 American Institute of Physics. [S0003-6951(99)01431-X].