Electron Quantum Correlation in in Semiconductor Quantum-Dot lattice Structures

点击翻译按钮获取中文摘要

Important quantum correlation effects such as quantum Hall effect and fractional quantum Hall effect have been revealed using the semiconductor two-dimensional electron system. In this system, applications to practical devices such as high speed FETs and lasers have also been achieved. In the lower dimensional systems, however, no prominent progress has been achieved in both fundamental research and device applications. A major reason to this lies on their poor geometrical accuracy. In the two-dimensional structures, the thickness of each layer has atomic size accuracy. However, in one- and zero-dimensional structures, side walls are quite rough. Moreover, structures produced by bottom-up.self-assembly process suffer from inhomogeneity and random distribution. In the present research, therefore, we adopted area-selective epitaxy by combining with e-beam lithograph and migration-enhanced epitaxy(MEE). We have succeeded in fabricating high quality one-dimensional electron wires and quantum dot lattices with AlGaAs/GaAs, InAs/GaAs, and InGaAs/GaAs. Atomically flat side walls of nano-structures are formed by utilizing micro-facet structures. To fabricate accurately the structures with designed ones, lateral growth should be minimized. This has been accomplished by optimizing the MEE deposition sequence. One dimensional wires exhibit ballistic transport characteristics. Two dimensional quantum dot lattices show unique transport characteristics. They have proved useful also for two-dimensional photonic crystals.