Spherical Nanolayers in Uniform and Radial Electrostatic Fields

In the strong quantization regime the single-particle states in quantum heterostructures core/layer/clad in conditions when the localization of charge carriers in the layer-component of composition takes place, are considered. Investigation was conducted both in the absence of an external field and in the presence of weak and strong homogeneous electrostatic fields as well as when the radially symmetric electric field is present. In the case of weak fields the confinement Stark effect in the layer is considered. Correspondingly, the energy shifts of the radial and orbital motions of charge carriers in the layer and corresponding perturbated envelope single-electron wave functions are calculated under the external homogeneous electrical field. The calculations are carried out separately for both cases of perturbation of the radial and orbital motions of charge carriers in the layer. The influence of a strong homogeneous electric field on the states of charge carriers in the structure of quantum dot-quantum well (QDQW) is studied theoretically. It is shown that a strong external field changes radically the character of carrier motion in the structure and leads to an additional fieldlocalization of the particle along the polarangle variable. An explicit form of the wave functions and energy spectrum of single-particle states in the structure in the presence of an external field is obtained. The possibilities of experimental and operational applications of the theoretical results obtained for the study of core/layer/shell structures as well as of hollow spheres are also shown. Explicit analytical expressions for the energy spectrum and the envelope wave functions in the presence of a source of the radial electrostatic field in the center of the heterostructure are obtained. The quantitative estimations for concrete CdS/HgS/CdS structure are given as well.

Keywords: Adiabatic approximation, Boundary conditions, Effective mass, Electric field, Energy spectrum, Moderate field, Perturbation theory, Probability distribution, Quantized layer, Quantum dot, Quantum well, Radial field, Space separation, Stark-effect, Strong field, Strong quantization, Uniform field, Variation method, Wave function, Weak field, WKB-approximation.