Localization effects in the tunnel barriers of phosphorus-doped silicon   quantum dots
  We have observed a negative differential conductance with singular gate and source-drain bias dependences in a phosphorus-doped silicon quantum dot. Its origin is discussed within the framework of weak localization. By measuring the current-voltage characteristics at different temperatures as well as simulating the tunneling rates dependences on energy, we demonstrate that the presence of shallow energy defects together with an enhancement of localization satisfactory explain our observations. Effects observed in magnetic fields are also discussed. 
T. Ferrus, A. Rossi, W. Lin, D. A. Williams, T. Kodera and S. Oda
cond-mat.mes-hall