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Journal of Nanomaterials
Volume 2013 (2013), Article ID 240563, 7 pages
http://dx.doi.org/10.1155/2013/240563
Research Article

Hydrogenic-Donor Impurity Binding Energy Dependence of the Electric Field in GaAs/AlxGa1−xAs Quantum Rings

1College of Science, Hebei United University, Tangshan 063000, China
2College of Light Industry, Hebei United University, Tangshan 063000, China

Received 11 June 2013; Revised 2 July 2013; Accepted 2 July 2013

Academic Editor: Yogendra Mishra

Copyright © 2013 Guangxin Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Using a variational method with two-parameter trial wave function and the effective mass approximation, the binding energy of a donor impurity in GaAs/AlxGa1−xAs cylindrical quantum ring (QR) subjected to an external field is calculated. It is shown that the donor impurity binding energy is highly dependent on the QR structure parameters (radial thickness and height), impurity position, and external electric field. The binding energy increases inchmeal as the QR parameters (radial thickness and height) decrease until a maximum value for a central impurity and then begins to drop quickly. The applied electric field can significantly modify the spread of electronic wave function in the QR and shift electronic wave function from the donor position and then leads to binding energy changes. In addition, results for the binding energies of a hydrogenic donor impurity as functions of the impurity position and applied electric field are also presented.