Nanostructures

In the previous chapter, we analyzed the relevant phenomena to the understanding of the junction between two semiconductors. These typically occur on the spatial scale of the depletion zone, which in silicon takes on typical values of the order of a micrometer. However, the development of semiconductor growth methods has made it possible to grow multilayers of semiconductors with thicknesses of the order of a few (even one) atomic layer, of the order of a few nanometers: the corresponding semiconductor structures are called nanostructures . In general, the reduction in dimensionality to the order of magnitude of the nanometer can occur in one or more of the three space dimensions, leading to thin-films (nanofilms), nanotubes or quantum dots. In this chapter, where a very brief introduction to this immense topic is intended, we will focus on the reduction in one dimension only (nanofilms).