The Transport And Optical Properties Of Single-electron Tunneling Coupled Quantum Dots

This thesis investigates the transport and optical properties of the single-electron transistor (SET), with an extra quantum dot joining the SET system. The optically excited main dot in the SET couples to the second dot through the electron-hole and hole-hole Hubbard-like interactions. Using the non-equilibrium Green's functions, the roles of the electron and hole complexes in the tunneling and emission processes in the system are disclosed.The thesis is organized as follows:The first chapter gives a brief introduction to the semiconductor quantum dots, where the concept of quantum dots, the more detailed description of some unique quantum effects of the quantum dots has been presented. Then we describe coupled quantum dot system, and the application of the quantum dots system to theoretical, experimental and industrial fields.In chapterⅡ, we introduce a p-type extra quantum dot, into the SET, the two dots electrostatically connected together. Using retarded Green's function method, we obtain characteristics of tunneling current's profile and analyze the effect of different hole occupation numbers in the second quantum dot on probability distributions of the full resonant mechanisms involved in tunneling processes.In chapterⅢ, we use the Keldysh nonequilibrium correlated Green's function method to calculate the spontaneous emission spectra of main quantum dot coupled with an n-type quantum dot sandwiched in the n-n junction. The effects of the exciton complexes on the spectra are analyzed in detail.The last chapter, chapter IV, gives the summary and perspective of the our work.