Sige Single Quantum Dots Of The Coupling And The Study Of Transient Electrical Properties

Semiconductor nanostructure shows great potential in application areas as opto-electronics, micro-electronics, and single-electron devices. Self-assembled GeSi quantum dots have one of major advantages of its compatibility with conventional Si integrated-circuit technology. Recent research on GeSi QDs concentrated on its average properties, which neglects the details on a single quantum dot.Conductive AFM (Conducive Atomic Force Microscopy) is a recently developed nanometer scale measurement which can get the morphology and electrical properties of nanoscale and has wide application in measuring microscopic properties of the samples. It makes direct investment of the electrical property of one single QD possible.In this paper, we studied coupled GeSi QDs and the transient charging of a single QD using CAFM. Main results are as follows.1. Multi-layer quantum dots shows vertical coupling effect, at the same time, quantum dots on the same layer shows lateral coupling effect when the density of the dots are high enough. In this paper,we looked into the coupling effect of multi-layer/densely packed GeSi QDs。We measure the I-V curve and current map of single-layer/multi-layer/high density/low density samples. We investigated and compared the coupling effect showed in their electrical properties.2. A novel current peak has been observed in the current-voltage characteristics measured on individual GeSi quantum dots in earlier research. The current peaks are detected only during the backward voltage sweep immediately after a forward sweep. This phenomenon is assumed to be due to the charge and uncharged process of the quantum dot. To prove this, we use a mathematical model to simulate this phenomenon. Compared to the experimental data, in which the current peak position and intensity are found to depend strongly on the voltage sweep conditions, the model works well.