Electron pump operation based on coulomb blockade devices using silicon-on-insulator material

摘要

During the last years, electron pumps and turnstile using Coulomb blockade devices have been investigated for applications in new physical standards.~(1-4) In these devices several ac signals with a particular phase relation were used to acieve a well defined current. These early experiments were carried out with single electron transistors (SETs) based on Al/Al_2O_3 systems or GaAs/AlGaAs heterostructures.~(4.5) Recently electron pump behaviour has been demonstrated in a GaAs based system at 1.8 K by using only one ac signal.~6 We describe here electron pump operation at 4.2 K in a silicon-based system with multiple tunnel junction (MTJs) SETs formed in highly doped silicon nanowires. In these nanowires the dopants create local fluctuations of the electrical potential. If appropriate gate voltages are applied to these wires, they break up into islands and tunnel barriers. Their characteristics can be described by Coulomb blockade and they are equivalent to single electron transistors.