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The use of finite confining potential well model for excitons in a cylindrical quantum wire indicated that for wire radii greater than a few Bohri radii, the contribution to the exciton linewidth calculated using this model agrees with the results for the infinite well model. However for smaller wire radii, the linewidth reaches a maximum value and then decreases due an increasing probability that the exciton would be found outside the wire in the surrounding barrier.

Reserach was conducted to measure the effect of an electric field applied along the direction of carrier confinement on the exciton linewidth due to the scattering of excitons by ionized impurities in semiconducting quantum well structures. It was found that the contributions to the linewidth increased with the applied electric field except for the narrowest wells. Also, the contribution to the linewidth due to elastic scattering of the exciton is many orders of magnitude larger than that due to scattering in which the exciton is ionized.

The two photon absorption (TPA) in semiconducting quantum wires and quantum boxes is calculated in the presence of an electric field. The TPA has more structure in quantum boxes than that in quantum wires for any direction of electric field or polarization and the ratio of the TPA in the quantum wires and boxes to that in the bulk is calculated as a function of the photon energy both in the presence and absence of the electric field.

A theoretical calculation of the effect of an electric field applied either parallel or perpendicular to the direction of confinement on the interband optical absorption of semiconducting nanostructures such as quantum wells, quantum wires, and quantum boxes are presented. The absorption of semiconducting nanostructures are found to be greater when the electric field is along the direction of carrier confinement than when it is perpendicular to the direction of carrier confinement.

The results of the effect of a transverse electric field on the ground and the first few excited states of the electrons confined in a quantum wire are used to examine the effects of the electric field o the intersubband optical absorption on such quantum wires. The findings state that for small wire radii and for strong electric fields, the infinite well model breaks down.

A variational wave function in cylindrical wires was used to calculate the dependence of photo ionization on hydrogenic impurities on the photon energy. It was found that the behaviour of the cross section varies for different polarizations.

The dependence of photoionization of the photon is calculated using a variational wave function for hydrogenic impurities in spherical quantum dots. The threshold energy for the photoionizations cross section is lower for off center impurities when the photons are polarized along the direction connecting the impurity with the center of the dot than it is for on center impurities or for off center impurities for photons polarized perpendicular to this direction.