Vanishing of the impurity binding energy in n-doped In0.53Ga0.47As/InP quantum wells

This study develops a variational approach to calculate the binding energy of a shallow hydrogenic impurity in a n-doped In0.53Ga0.47As/InP single quantum well. Using a proper trial wavefunction, both Schrödinger and Poisson equations were solved simultaneously within the effective mass approximation, taking into account finite well barriers, finite temperatures, and different effective masses and dielectric constants along the growth direction. Band bending, screening, and many-body effects were considered and it is found these effects reduce drastically the impurity binding energy and lead to the vanishing of this energy when the 2DEG density reaches a critical value. Our results show that such a vanishing occurs even for very thin quantum wells, contrarily to recent calculations developed for GaAs/AlGaAs quantum wells.