Electric field effects on the electronic states in a triangular prism nanocrystal

The effect of applied electric fields on the binding energy and polarizability of a donor impurity in a prism-shaped GaAs quantum dot with triangular cross-section is theoretically investigated. Calculations have been made in the effective mass and parabolic band approximations by using a finite element method. The results are reported for the ground and the first excited states of an on-center donor when the electric field is applied along different directions of the quantum dot. We found that the variation of the binding energy reflects the spatial distributions of the electron wave functions, which significantly changes when the electric field is varied. In this low-symmetry system the impurity polarizability exhibits a strong dependence on the applied field direction.