Fabrication of Quantum Wires Based on Selective Doping Mechanism and Its Application to Functional Devices Using Quantum Parallelism

我们的目标是建立我们原创的量子线制造方法，并进一步发展该方法以应用于“量子器件”的实现。除了（100）GaAs衬底外，我们还研究了在（311）A GaAs衬底上生长的量子线的制造和电子特性。量子线晶体管的低温测量显示出清晰的量子线特性。主要结果如下所述。（一）建立了一种基于图案衬底上选择性掺杂机制的器件级量子线制备新方法。与电子束光刻或扫描探针法等先进的纳米光刻技术不同，本方法能够在一步生长中加工晶圆级精细结构。通过静电力显微镜观察，得到的量子线沿mm长的结构保持高质量。（ii）在2K的掐断条件下，观察到更多的单电子振荡。改变温度和外部磁场的详细测量表明，沿着量子线的电位起伏导致了一系列大约6meV深的孤立电位口袋。结果显示了基于该方法的沿mm长的量子线的约束势的平整度。此外，我们已经观察到明显的电导振荡，这是在77K和4K下一维传导的明显证据。这一结果有力地表明，一维传导可以在77K或更高的温度下实现，而无需模式混合。（iii）对“单线”晶体管的晶体管特性也进行了研究。I。5μm栅极晶体管在300K和77K时的跨导分别为580mS/mm和650mS/mm。这些结果属于GaAs/AlGaAs调制掺杂晶体管的高端。这一结果表明我们成功地制造了高质量的一维电子系统。它还显示极小的栅漏电流，数量级为几十皮安。结合这种低漏特性，量子线方法具有基于经典原理和量子功能原理的集成量子量子晶体管电路的高潜力。少

We have aimed at establishing our original fabrication methods of quantum wires and further developing the method to apply to the realization of the "quantum devices". We have investigated the fabrication and the electronic characterization of the quantum wires grown on facets on (311)A GaAs substrates in addition to the (100) GaAs substrates. Cryogenic temperature measurement on quantum wire transistors showed clear quantum wire characteristics. The major results are described below. (I) We have established a new fabrication methods of device quality quantum wires based on selective doping mechanism on patterned sustrates. Unlike the advanced nano-lithography technique such as electron beam lithography or scanning probe method, the present method was demonstrated to be able to process wafer scale fine structures in one step of growth. The obtained quantum wires were shown to maintain high quality along mm long structurally by Electrostatic Force Microscopy. (ii) Single electron oscill … More tion was observed near pinch-off conditions at 2K. Detailed measurements changing temperature and the external magnetic fields relealed that the potential ondulation along the quantum wire resulted in series of isolated potential pockets of 6meV or so deep. Present results shows degree of flatness of the confinement potential along the mm long quantum wires based on the present method. In addition, we have observed clear conductance oscillations which are clear evidence of 1-dimensional conduction at 77K and 4K. This result strongly indicates that one-dimensional conduction is achieved at up to 77K or more without mode mixing. (iii) Transistor characteristics of the "single wire" transistor were also investigated. The I .5μm gate transistor showed the transconductance of 580mS/mm and 650mS/mm at 300K and 77K respectively. These results belong to high end of the modulation doped transistors based on GaAs/AlGaAs. This result indicates successful fabrication of high quality one-dimensional electron systems. It also revealed extremely small gate leakage current of the order of tens of picoamperes. Together with this low leakage characteristics, the present quantum wire approach was shown to have high potentail of integrated quantum qire transistor circuits based on classical and quantum funcional principles. Less