Open Access Nano Express

Donor impurity-related linear and nonlinear intraband optical absorption coefficients in quantum ring: effects of applied electric field and hydrostatic pressure

Manuk G Barseghyan1, Ricardo L Restrepo2, Miguel E Mora-Ramos34, Albert A Kirakosyan1 and Carlos A Duque4*

Author Affiliations

1 Department of Solid State Physics, Yerevan State University, Al. Manookian 1, Yerevan, 0025, Armenia

2 Escuela de Ingeniería de Antioquia, Medellín, 7516, Colombia

3 Morelos State University, Cuernavaca, 62209, Morelos, Mexico

4 Instituto de Física, Universidad de Antioquia, Medellín, 1226, Colombia

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Nanoscale Research Letters 2012, 7:538  doi:10.1186/1556-276X-7-538

Published: 28 September 2012

Abstract

The linear and nonlinear intraband optical absorption coefficients in GaAs three-dimensional single quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and electric field, applied along the growth direction of the heterostructure, the energies of the ground and first excited states of a donor impurity have been found using the effective mass approximation and a variational method. The energies of these states are examined as functions of the dimensions of the structure, electric field, and hydrostatic pressure. We have also investigated the dependencies of the linear, nonlinear, and total optical absorption coefficients as a function of incident photon energy for several configurations of the system. It is found that the variation of distinct sizes of the structure leads to either a redshift and/or a blueshift of the resonant peaks of the intraband optical spectrum. In addition, we have found that the application of an electric field leads to a redshift, whereas the influence of hydrostatic pressure leads to a blueshift (in the case of on-ring-center donor impurity position) of the resonant peaks of the intraband optical spectrum.

Keywords:
GaAs; Quantum ring; Optical absorption; 78.67.De; 71.55.Eq; 32.10.Dk