chapter  12
14 Pages

Quantum Dots

WithNelson Bolivar, Gabriel Abellán

The quantum dots (QDots), also known as low-dimensionality heterostructures or artificial atoms, are solid semiconductor structures, composed mainly of Gallium Arsenide (GaAs), Arsenide de Galium-Aluminum (GaAsAl), Cadmium Selenide (CdSe), or Galena (PbS). The QDots act as a box that confines particles, whether electrons, holes or excitons, the numbers can be controlled by applying a potential across two metal electrodes connected to the system. As mentioned before, Qdots have dimensions, and the number of atoms between the molecular atomic level and bulk materials with a band interval depends in a complex way upon a number of factors, including the type of bond and strength with the nearest neighbors. A very unique property of the Qdots is the quantum confinement, which modifies the DOS near the edges of the band. Qdots exhibits a solid-solid phase transition as bulk semiconductors. Phase transitions in bulk materials can be induced by variable pressure, temperature and composition.