Uniaxial stress dependence of the binding energy of shallow donor impurities in GaAs–(Ga,Al)As quantum dots

Abstract

We have studied the effects of an uniaxial stress on the binding energy of a shallow donor impurity in a parallelepiped-shaped GaAs–(Ga,Al)As quantum dot. In the calculations we have used a variational technique within the effective-mass approximation. The stress was applied in the z direction and the donor impurity was located at various positions along the z axis. Our results show that the donor binding energy increases with increasing stress and for decreasing sizes of the quantum dot. Also, we have found that the binding energy for various values of the donor position along the z axis for constant quantum well box size increases with the proximity of the impurity to the center of the structure. Moreover, we obtain the shallow-donor binding energies as functions of uniaxial stress in the limit in which the quantum dot turns into either a quantum well or a quantum-well wire.

Binding energy and photoionization cross-section in GaAs quantum well-wires and quantum dots: magnetic field and hydrostatic pressure effects

“…In the last two decades many works related with the magnetic fields effects on the properties of the electron-impurity systems have been reported in GaAs − Ga 1−x Al x As quantumwell wires (QWWs) and quantum dots (QDs) [4][5][6]. The effects of hydrostatic pressure on such systems, and in particular on the photoionization (PI) cross-section, show that the PI depends strongly on the symmetry of the potential that confines the carriers, of the energy of the incident photon, and of the impurity distribution inside the heterostructure [7].…”

Hydrostatic pressure effects on the donor impurity‐related photoionization cross‐section in cylindrical‐shaped GaAs/GaAlAs quantum well wires

“…(1) without the impurity potential term and the eigenvalue associated with the wave function in Eq. (3) minimized with respect to the variational parameter λ [9].…”

“…Elabsy [4] has calculated the effects of the hydrostatic pressure on the binding energy of donor impurities in quantum well heterostructures, finding that the binding energy increases with increasing external hydrostatic pressure for a given quantum well thickness and temperature. Oyoko et al [9] have studied the effects of a uniaxial stress on the binding energy of shallow donor impurities in parallelepiped-shaped GaAs/GaAlAs QDs. They have found that the binding energy increases almost linearly with applied stress and diminishes with the sizes of the structure.…”

Effect of the dielectric-constant mismatch and magnetic field on the binding energy of hydrogenic impurities in a spherical quantum dot

“…The effect of an electric field on the electronic states and binding energy of a hydrogenic impurity in QD's is considered in [21,27], and the uniaxial stress dependence of the binding energy of shallow donor impurities in a parallelepiped-shaped QD is studied in [28]. It was shown that the binding energy increases with increasing stress of the QD and also with the proximity of the impurity to the center of the QD.…”