Using the effective mass approximation and the transfer matrix formalism, we have calculated the ground state energy of
electron in 0.7 0.3 GaAs/Ga0.7Al0.3As concentric double quantum rings under the combined effects of electric field and
hydrostatic pressure. The ground state energy dependences on the electric field, hydrostatic pressure and width of outer
ring are reported for different values of the thickness of rings. We have found that for low pressure regime (less than
P = 8.37 kbar ) the ground state energy decreases slower than for high pressure regime (higher then P = 8.37 kbar ).
Additionally, we have found that the effect of hydrostatic pressure on ground state energy mainly depends on the electric
field strength and the sizes of quantum ring.
Using the effective mass approximation and a variational procedure, we have calculated the effects of confining
potential and growth-direction applied magnetic field on the binding energy and photoionization cross section of a donor
impurity in a cylindrical InAs Pöschl-Teller quantum layer. We report the binding energy dependencies on the height and
the inner and outer radii of the cylindrical layer, the applied magnetic field, and the parameters of the Pöschl-Teller
confining potential. The dependencies of the impurity-related photoionization cross section on the incident photon
energy for the different values of the confining potential parameters and the geometrical parameters of the
heterostructure have been also considered. The results show that the impurity related binding and energy photoionization
cross section are non monotonic functions of the inputs here considered. Particularly, it is shown that the binding energy
increases with the increase inner radius of the layer and decrease with the all another inputs considered in this work
(height and outer radius of the layer, applied magnetic field, and asymmetry of the Pöschl-Teller potential). In the case of
the photoionization cross section the results show that with changes in the dimensions of the heterostructure and in the
symmetry of the potential both blue shift and/or red shift of the maximum of the lineshape can be induced.