The Study Of Tunneling Mechanism Between Different Dimensional Electronic States In Semiconductors

In this thesis, tunneling transport between different dimensional electronic states was studied systematically. The transfer matrix method and the Hamiltonian method were compared to analysis tunneling between different dimensional states. Numerical simulation was utilized to describe the dependence of the tunneling rate between low-dimensional states on the parameters of different dimensional states in nanocrystalline/crystalline Si heterojunction. The tunneling from two dimensional state to one dimensional state was analyed. The transfer Hamiltonian method was used to derive the tunneling expressions in double-barrier structures of different dimensional emitters. Further, the general expression of tunneling between different dimensional states was explored.First, the different dimensional tunneling transport systems were descriped abriefly. The tunneling rate of a quantum well to a quantum dot was theoretically inferred by means of a quantum mechanical model of a two-dimensional quantum well coupled to a zero-dimensional quantum dot, based on the transfer Hamiltonian method. In the case of nanocrystalline/crystalline Si heterostructures, influences of the parameters such as the quantum-dot size of nanocrystalline Si, the width as well as depth of interface quantum well on the tunneling rate were investigated with numerical simulation. The results indicate that tunneling rate has peak values under different size of the quantum dot, and it reduces with the increasing width and depth of quantum well. The device's performance should be considered on the size of the quantum dot, the width and the depth of the quantum well for the device design.Second, the tunneling rate of a quantum well to a quantum wire was theoretically inferred via a quantum mechanical model of a two-dimensional quantum well coupled to a one-dimensional quantum wire, based on transfer Hamiltonian method. The tunneling transport rate of the Si heterojunction interface to the Si nanowire quantum was simulated. The results showed that the tunneling rate increased with increasing applied voltage or with increasing the quantum wire radius, which might provide the train of thought for designing nanoelectronic devices based on transmission channel by silicon nanowire and enlighten other low-dimensional semiconductor devices.Finally, the tunneling transports between different dimensional states was analyed systematically, the transfer matrix and transfer Hamiltonian methods were comparative for solving the characteristics of tunneling transport properties, the transfer Hamiltonian was used to derive the tunneling expressions in double-barrier resonant-tunneling structures of different dimensional emitters, and the general expression between different dimensional tunneling was summarized.