Quantum Dots: Spectroscopy of Artificial Atoms.

Semiconductor quantum dots are fascinating objects, since, in some respect, they can be regarded as artificial atoms [1]. Figure 5.1 shows a very schematic comparison of a real three-dimensional atom and a disc-shaped quantum dot. The structure of real atoms is three-dimensional, while most of the artificial quantum dots can be regarded as large Q2D atoms, since the lateral dimensions are in most cases much larger than the vertical extension. Of course, a crucial difference between the two systems is the shape of the confining potentials, which, for real atoms is essentially the Coulomb potential of the nucleus, and, for quantum-dot atoms in some approximation a two-dimensional parabolic potential. [ABSTRACT FROM AUTHOR]