OPTICAL CHARACTERIZATION OF QUANTUM WIRES AND QUANTUM DOTS

Different optical techniques are described for the characterization of low-dimensional semiconductor structures like quantum wires and quant um dots. The main motivation for the strong interest in these structur es stems from the unique properties in terms of tunable electronic str ucture and related properties. Progress in applications of such quantu m structures is, however, limited by the poor control of their geometr ical distribution, leading to strong, inhomogeneous broadening. New te chniques are thus needed which allow the study of individual quantum s tructures and, hence, to learn more about the electronic properties. T hree main techniques are described: photoluminescence in its macroscop ical as well as microscopical form, cathodoluminescence, and luminesce nce induced by a scanning tunneling microscope. These techniques are i llustrated by optical characterization of quantum wire structures grow n on patterned substrates and of quantum dots formed by the Stranski-K rastanow mechanism.