Theoretical Research into Solid State Devices Suitable for Submillimetre Operation

摘要

The development of novel devices using submicron technologies is dependent upon a detailed understanding of the electronic properties at a quantum mechanical level. This report describes two related investigations into electron states and plasmons in heterojunction based quasi two dimensional systems formed from alternating layers of semiconductor material. It is found that the electron dynamics are no longer described by effective mass theory. Intervalley scattering, the excitation of localised states at the interfaces and the details of the electronic bandstructure are all important. Results are presented for electron scattering in the GaAs-GaAlAs system and resonant tunnelling through multiple barriers investigated. The plasmon modes are calculated by a new method which includes well widths, subband structure and multiple layers. This method allows the electron interaction in such a system to be calculated directly. The consequences of this program for submicron device design are described and further work suggested. Keywords include: Semiconductor, Devices, Heterojunctions, Superlattices, Quantum Wells, Interfaces, Submicron Structures, Tunnelling, Plasmons, GaAlAs Alloys, Electron Transport, and Bandstructures.