Theoretical Study for Negative and Positive Charges in Semiconductor Quantum Dots

Abstract

In this dissertation we study the dependence of binding energy and stability of positive and negative charges on the variation of external tunable parameters such as the geometry of the dot, the confinement potential, and an applied lateral electric field. We introduced a trial wave function not only to satisfy the strong confinement regime, but also to yield the correct results in the weak confinement regime inside the 3-D quantum dots (QDs). Utilizing such a trial wave function, we will follow the variational procedures to solve Schrodinger's equation within the effective mass approximation. Here, we focus on a charged exciton, negative donor and positive donor that are confined inside a full 3-D cylindrical quantum dot, with finite confinement square and parabolic potential. The study of the mentioned binding energy will be easily calculated at the limit of other nanostructures such as quantum well wires and the quantum well owing to the good choice of our anisotropic trial wave function. The structure of the present Dissertation is the following:

•In Chapter 1 we briefly review the construction of the semiconductors as nano­ structures, such as quantum well wires, quantum wells, and quantum dots. The Chapter is a primer about the quantum dots structures which is essential throughout this work, where we focus on the theoretical models that treat the electronic structure of such nano-structures, and also we present brief words about the experimental methods by which these quantum dots can be experimentally fabricated.