Electric Field Effect on the Energy of an Off-Centre Donor in Quantum Crystallites

Abstract

The quantum size, impurity position and electric ¢eld e¡ects on the energy of a shallow donor placed anywhere in a GaAs spherical quantum crystallite embedded in Ga 1Àx Al x As matrix are studied theoretically in the framework of the e¡ective mass approximation. The impurity is supposed on the z-axis. The conduction band o¡set between the crystallite and the matrix is assumed to be ¢nite. The ground state energy and the spatial extension of the unperturbed hydrogenic donor are determined by Ritz's variational method. It appears that for a ¢xed size of the crystallite, the energy and the spatial extension increase monotonically when the impurity is displaced from the centre to the surface of the crystallite. The in£uence of a uniform electric ¢eld F is analysed. It is found that for a donor placed at the centre of the crystallite, the energy level is shifted to low energies. However for an o¡-centre donor the energy level shift depends on the angle between F and z.

Effect of charge carrier–phonon coupling on the energy of shallow donors in CdSe quantum dots

“…(14), we use Hassé's variational method [33] adapted to SQDs in our previous works [13,14]. The trial wave function is given by the following expression:…”

“…Indeed, in a confined medium the electric field leads to a quantum confined Stark effect [9][10][11][12] characterized by a red shift many times greater than the electron-hole binding energy. In our previous works [13,14], using a variational approach and neglecting the polaronic effect, we have studied the simultaneous effects of magnetic and electric fields on the binding energy of a donor confined in an infinite potential. We have shown that the magnetic field reduces the spatial extension of the wave function and leads to a decrease of the donor polarizability.…”

Lateral electric field effects on quantum size confinement in cylindrical quantum dot under parabolic potential

“…Many studies concern the electric field effect on QDs [10][11][12][13][14] and the properties of both neutral and charged donors in nanostructures under electric field effect are a subject of large amount of both theoretical and experimental investigation [15][16][17][18][19][20]. In Ref.…”

Finite-Barrier Height Effect on the Polarizability of a Shallow Magneto-Donor in a Quantum Box

“…The effect of the magnetic field on the polarizability of a shallow donor in a QD has been analyzed by Feddi et al [22], using an infinite confinement potential case. For a realistic case of a finite height confining potential Assaid et al [23] have calculated the polarizability for a quantum dot without magnetic field.…”