Modulation of Coulomb Blockade Behavior of Room Temperature Operational Single Electron Transistors by Tunnel Junction

The effect of tunneling oxide thickness on the Coulomb blockade behavior of a room temperature operating multi dot Single Electron Transistors (SET) was investigated. Our room temperature operational SETs, fabricated from focused ion beam deposited tungsten nano-islands, clearly show the modulation of Coulomb Blockade voltage with the change in the tunnel oxide thickness. The Coulomb blockade voltage of the device was increased from 2.0 V to 5.0 V by the reduction of tunnel junction thickness from 9 nm to 3 nm. In the present experiment, a decrease in the thickness of the tunneling oxide resulted in an increase in the conductance and tunnel current of the device by two orders of magnitude. The total capacitance of the SET device was reduced from 0.7 atto F to 0.5 atto F with the reduction in the thickness of the tunnel junction thickness of the SET. The charging energy of the SET device was increased from 110 meV to 146 meV with the reduction of the tunnel junction thickness from 9 nm to 3 nm, the modulation of the Coulomb blockade voltage was achieved with the variation in the tunnel junction thickness of the SET device.