Nanocrystalites: Building blocks for quantum dot heterostructures

The electronic structure of semiconductor quantum dots has been explored. The picture that emerges is of quantum confined, atomic-like states which are delocalized throughout the particle. The states appear to be reasonably well described using the bulk band structure, simply applying finite boundary conditions at the interface between the dots and their surroundings. Ultra-narrow transition linewidths and large polarizabilities further confirm the atomic-like and delocalized character of the electronic states. Semiconductor dots can be manipulated to form a number of structures. The quantum dots can be combined with charge transporting semiconducting polymers to make light emitting or photovoltaic devices. The dots can be incorporated into traditional semiconductor thin films which can themselves be doped and incorporated into layered structures. Finally, the dots can be close packed into both glassy and crystalline structures with long range translation symmetry.