Line Widths of Single-Electron Tunneling Oscillations: Experiment and   Numerical Simulations
  We present experimental and numerical results from a real-time detection of time-correlated single-electron tunneling oscillations in a one-dimensional series array of small tunnel junctions. The electrons tunnel with a frequency f=I/e, where I is the current and e is the electron charge. Experimentally, we have connected a single-electron transistor to the last array island, and in this way measured currents from 5 fA to 1 pA by counting the single electrons. We find that the line width of the oscillation is proportional to the frequency f. The experimental data agrees well with numerical simulations. 
Jonas Bylander, Tim Duty and Per Delsing (Chalmers University of   Technology, Sweden)