Transport Spectroscopy of Single and Coupled Quantum Dots in Single Electron Tunneling

Abstract

In recent years interest arose into the study of transport through quantum dots. The interest is driven by two reasons. First, small devices like quantum dots and charging effects [1] In such devices open the possibility for future applications in electronics as transistors, memory cells, sensors etc. Small devices are especially interesting in high frequency applications due to their small capacitances. Although different schemes for applications have been proposed, none of it is under development or even in production and it is not clear what will be of real use in the end. The second reason for the interest into these systems is a basic physics point-of-view. These systems are extremely interesting since single quantum dots can be seen as a sort of artificial atom. In this manner-of-speaking coupled quantum dots can be called artificial molecules. These quantum dots are similar to atoms or molecules since a certain number of electrons is confined in a potential. But, in contrast to real atoms, in these artificial systems the number of electrons, the size of the system and the strength of the confinement potential can easily be changed. Therefore, in these quantum dots parameters, such as the ratio between cyclotron frequency and confinement energy or coupling strength between two quantum dots etc, can be easily varied, which is not achievable in real atoms or molecules.