Stability of neutral and negative donor impurity in a semiconductor cylindrical quantum dot

The stability of neutral (D⁰) and negative charged donor (D⁻) on- and off-center in anisotropic cylindrical quantum dot (CQD) is studied by use of a variational approach. Two-parameter anisotropic trial wave function which includes electron-correlation effects is utilized, to explore strong and weak confinement regions. A comparison between one and two-parameter trial wave functions results is introduced. The finite barrier height and the CQD dimensions, dependence of the “stability and the binding energy” of the D⁰ and the D⁻ is obtained. It has been shown that the donor's stability dependent on CQD dimensions and the confinement potential in strong confinement region but in weak confinement region, the stability of D⁰ and D⁻ is dependent strongly on the quantum dot (QD) radius R. It has been found that the donors D⁰ and D⁻ off-center are less stable than the on-center impurities, and also the off-center donors more stable in small CQDs. It has shown that the stability of D⁻ depends on the energy of the excess electron.