Single electron transport in resonant tunnelling diodes laterally confinedby ion implantation

In order to investigate single electron transport the lateral dimensions of a resonant tunnelling diode have been confined to the submicrometre range by oxygen ion implantation. Depending on the temperature sequence used in t he annealing step subsequent to the implantation, these small area resonant tunnelling diodes in the single electron regime either show clearly develo ped staircase-like features asa consequence of single electron tunnelling t hrough discrete zero-dimensional states or a sequence of current peaks due to single electron tunnelling through coupled zero-dimensional states. Magn etotransport measurements suggest impurity states related to implantation d efects as an origin of the zero-dimensional states.