SHALLOW DONORS IN A COUPLED TRIPLE GRADED QUANTUM WELL UNDER THE ELECTRIC AND MAGNETIC FIELDS

The binding energy of the donor in three different shaped triple graded GaAs-(Ga, Al)As quantum wells which is obtained by changing the depth of the central-well potential (Vo) is calculated by using a variational approach. The results have been obtained in the presence of uniform magnetic and electric fields applied along the growth direction as a function of the impurity position. In addition, we also give the binding energy of the hydrogenic donor impurity for triple square quantum wells having the same physical parameters with triple graded quantum well structures in order to see the effect of different geometric confinements on the donor impurity binding energy.