Approaches to Quantum Transport in Semiconductor Nanostructures

Abstract

Our view of electronic transport in nanostructures is based on semiconductor technology and aims at the development of numerical methods that are applicable in virtually arbitrary geometrical structures. By semiconductor technology we refer to existing technology as it has been presented in this summer school but also to future technological possibilities that appear on the horizon. The conventional methods of pattern fabrication appear to be able to produce systems that show mesoscopic effects only at very low temperatures. However, it is conceivable that structures can be fabricated, even on silicon, that will exhibit waveguide-like properties at 77 K and maybe even at room temperature. Pattern generation by tunneling microscopy techniques has been demonstrated on silicon surfaces with feature sizes of around 100 A and below (Loenen et al., 1989). Patterns of these sizes promise not only the information of the library of congress on square inch dimensions but also the smallness which is necessary to produce electron waveguides or general quantum interference phenomena at high temperatures. In fact, recent estimates show that silicon-silicon dioxide structures written with tunneling microscopy methods will enable us to investigate a wide range of quantum effects far above the temperatures where they are observed now (Lyding et al., 1990).