Effect Of Field On Excitations In InPBi Low - Dimensional Semiconductor Structures

With the development of molecular beam epitaxy and metal organic chemical vapor deposition, it is possible to fabricate various kinds of artificial low-dimensional semiconductor heterostructures. They exhibit special optical and electrical properties which reflect in the increasing use of these heterostructures in optoelectronic devices. The theoretical research of exciton states of low-dimensional semiconductor materials are meaningful and can be utilized for designing the optical communication devices.Exciton binding energies in InAlAs/InPBi/InAlAs low-dimensional semiconductor heterostructures are calculated using the variational method in the effective mass approximation in this paper, the main contents are presented as following:1. The application of low-dimensional semiconductor materials in optical communication and the dilute bismuth material are introduced, and the exciton is also introduced in detail.2. The theoretical research methods of calculating exciton binding energy in low-dimensional semiconductor heterostructures are introduced systematically.3. Exciton binding energies in InAlAs/InPBi/InAlAs low-dimensional semiconductor heterostructures are calculated using the variational method in the effective mass approximation. The results show that the exciton binding energy first increases and then decreases with increasing well width in quantum well. The Bohr radius decreases with the increase of the well width firstly and then increases. This is the result of quantum confinement potential and coulomb potential. The increasing of Al and Bi component leads to increase of the exciton binding energy. The position of binding energy maximum value is different because of different Al and Bi components. At the same time, the results show that exciton binding energy first increases up to its maximum, then begins to decrease as the quantum wire and quantum dot radius increases in quantum wire and quantum dot. This is the same as the change of the exciton binding energy in quantum well.4. The effects of the applied electric field on exciton binding energy in In AlAs / InPBi / InAlAs low-dimensional semiconductor heterostructures are mainly discussed. The results show that when the well width is larger, the influence of the applied electric field on the exciton binding energy is larger. It is shown that effect of electric field within a certain range on the exciton binding energy is small. However when the applied electric field is large enough, it will destroy the excitonic effect. In addition, The influence of external electric field on exciton binding energy in quantum wire and quantum dot is similar to that of the exciton binding energy in quantum well.5. The effects of the applied magnetic field on exciton binding energy in InAlAs / InPBi / InAlAs low-dimensional semiconductor heterostructures are mainly studied. The results show that exciton binding energy presents monotonous increasing tendency with the increase of the applied magnetic field in quantum well, and the amplitude increase more greatly. When the well width is smaller or larger, the influence of the applied magnetic field on the exciton binding energy is larger. At the same time, the larger the additional magnetic field is, the greater the exciton binding energy is in quantum wire and quantum dot. The influence of external magnetic field on exciton binding energy in quantum wire and quantum dot is similar to that of the exciton binding energy in quantum well.