Study of hydrostatic pressure, electric and magnetic fields effects on the donor binding energy in multilayer cylindrical quantum dots

Abstract

The current paper provides a theoretical study of the binding energy of an off-center donor impurity in wurtzite InGaN/GaN multilayer cylindrical quantum dots (MCQDs). The Schrödinger equation related to the shallow donor impurity has been solved by the finite element method (FEM) using a parabolic confinement potential in the radial direction and a square one in the z direction within the effective-mass and a parabolic conduction band approximation. Furthermore, we have studied the external perturbations on the donor binding energy such as: hydrostatic pressure, magnetic and electric fields as well as the effect of strain induced by the lattice mismatch. Moreover, the binding energy has been calculated as a function of the geometric parameters of the structure, indium concentration x in the InxGa1−xN alloy and impurity position z0. Our main findings show that the binding energy is more influenced by the electric field for large sizes, by the hydrostatic pressure and the magnetic field for all sizes, especially for wide radius R, barrier Lb and thin Ld. Additionally, the results show that the lattice mismatch has an impact on the binding energy, mostly at low pressure.