Theoretical study of positive and negative donor impurity in quantum dot, quantum well limit and quantum wire limit

Abstract

We compare the binding energy of positive (D +) and negative (D −) charged donor impurities on- and off-center confined in a fully three dimension (3-D) anisotropic cylindrical quantum dot (CQD) with a finite barrier height. Two-parameter anisotropic trial wave function is used, to explore the quantum wire wells (QWW), and the quantum well (QW) limits. A quantitative study for the behavior of the binding energy of D + and D − is introduced. It has been shown that the donor's binding energies dependent strongly on CQD radius R, and it has been found unexpected behavior of D +. The complex, when D 0 bound heavy or light hole to form ( D hh + ) or ( D 1 h + ) , the binding energy is examined. It has been concluded that D 1 h + is more bounded (higher binding energy) than D hh + . Moreover for a certain CQD we have calculated the binding energy of the off-center impurities. It has been found that D + binding energy increases when impurity ion is moved away from the center of the examined nanostructures, but the D − binding energy decreases when impurity ion moves away from the center.