Intense field effects on shallow donor impurities in graded quantum wells

Abstract

Using a variational method and within the effective mass approximation, we calculate the laser-field dependence of binding energy and the polarizability of shallow-donor impurities in graded quantum wells under an external static electric field. We have shown that, in the graded quantum well structures, not only the 'dressed' potential but also the direction of the external electric field parallel to the growth direction play very important roles in the determination of the binding energy and the polarizability of a hydrogenic impurity.

Density of impurity states of shallow donors in a quantum well under intense laser field

“…6-9. We notice that for wider QWs, as the electron wave function becomes more spread out, the laser field effect on the binding energy diminishes. This is in agreement with the results obtained for on- center donors in low dimensional systems [8,12]. Note that our on-center binding energy values in an L = 200 Å QW are in good agreement with the results of Sari et al [8].…”

“…In the effective-mass approximation, the behavior of an electron bound to a donor impurity in a QW under an intense laser field may be described by the Hamiltonian [8,10]:…”

“…Sari et al [8] have studied the laser-field dependence of the binding energy and the polarizability of an on-center donor in a graded quantum well under an external electric field. Brandi et al [9] have extended the dressedatom approach to treat the interaction of the laser field with a semiconductor system in which the interaction with the laser is taken into consideration through the renormalization of the semiconductor effective mass.…”

Effects of laser field and electric field on impurity states in zinc-blende GaN/AlGaN quantum well

“…In the presence of laser field and electric field, the timedependent Schrödinger equation describing the electron in ZB GaN/AlGaN QW was given as follows [20] −h…”

“…here V c ( α 0 , r) is the 'dressed' Coulomb potential, which can be written as follows [20] 2 is the distance between the electron and the impurity site, x(0), y(0) and z(0) are the coordinate electron (impurity) in the QW.…”