The Study Of Coulomb Blockade In Single Electron Transport Produced By Surface Acoustic Wave

The mesoscopic physics, which developed rapidly from the beginning of 1980s, is a remarkable field in condensed matter physics with many new effects discovered. It has great significance to the basic study of semiconductor physics, semiconductor device and its application.The interaction of a surface acoustic wave (SAW) with a two-dimensional electron gas (2DEG) in a GaAs/Al_xGa_1-xAs heterojunction through piezoelectric effect has recently attracted much attention. The acoustic wave is attenuated due to interaction with the electrons while traveling across the sample, and transfers some of its momentum to the electrons. As a result a d.c. voltage in an open circuit appears. In a closed circuit, a d.c. current is generated (the acoustoelectric current).In this thesis we studied the device of single electron transported by SAW at extremely low temperature (approximately 0.260K), and observed in China the acoustoelectric current which is induced by SAW transporting electrons from source area to drain area. Under the condition of a suitable split gate voltage, the source-drain current is zero when the source-drain voltage is lower than a threshold value. This phenomenon is called Coulomb Blockade. When the source-drain bias was fixed, we observed the Coulomb Blockade Oscillation that the source-draincurrent is an oscillatory function of split gate voltage. We determined the resonance frequency of inter-digital transducer (DDT) by measuring the source-drain current when different frequency microwave signals were coupled to IDT. The acoustoelectric current also reveals Coulomb Blockade as a function of split gate voltage when microwave signal with the resonance frequency is coupled to DDT. The phenomena of Coulomb Blockade and Coulomb Blockade oscillation are interpreted by the theory of electrostatic model of Coulomb blockade.