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 Schrodinger 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. (C) 2002 Elsevier Science B.V. All rights reserved.