Dynamics of a charged fluctuator in an Al-AlOx-Al single-electron transistor

We report detailed observations of random-telegraph charge fluctuations in a two-junction Al-AlOx-Al single-electron transistor (SET) switched between two states, causing charge shifts of DeltaQ(o) = 0.1 +/- 0.025e on the SET 's island. The transition rate out of each state was periodic in the gate v oltage, varied non-monotonically with the device bias voltage, and was inde pendent of the temperature about 0.3 K. We discuss two effects which could contribute to the behavior of the transition rates, including heating of th e defect by the island conduction electrons and inelastic scattering betwee n the defect and electrons flowing through the SET.