Worldwide, many researchers are fascinated from the rich physics of semiconductor
quantum dots (QDs) and their high potential for applications in
photonics and quantum information technology. QDs are nanometer-sized
three-dimensional structures which confine electrons and holes in dimensions
of their corresponding De Broglie wavelength. As a result, the energy levels are
quantized and for that reason they are also often referred as artificial atoms.
Epitaxially grown QDs which are the subject of this book are embedded in a
solid state semiconductor matrix and their size, shape, composition, and location
can be tailored to a large extent by modern growth techniques. In QDs,
excitations can involve more than a single carrier and interaction among the
carriers modify or even dominate the emission properties. Therefore, a simple
two-level description is only appropriate under certain well defined experimental
conditions. Tremendous progress has been obtained in understanding
their electronic, optical and spin properties mainly by performing single dot
spectroscopy and using appropriate theoretical models