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，并进一步开发该方法以应用于“量子器件”的实现。除了 (100) GaAs 衬底之外，我们还研究了 (311)A GaAs 衬底面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。主要结果描述如下。 （一）我们建立了一种基于图案衬底选择性掺杂机制的器件质量量子线的新制造方法。与先进的纳米光刻技术（例如电子束光刻或扫描探针方法）不同，本方法被证明能够在一个生长步骤中处理晶圆级精细结构。静电力显微镜显示，所获得的量子线在毫米长的结构上保持了高质量。 (ii) 在 2K 的夹断条件附近观察到单电子振荡。详细测量温度变化和外部磁场表明，沿着量子线的电势波动导致了一系列 6meV 左右深的隔离电势袋。目前的结果显示了基于本方法的沿毫米长量子线的限制势的平坦度。此外，我们还观察到明显的电导振荡，这是 77K 和 4K 时一维传导的明显证据。该结果有力地表明，在高达 77K 或更高温度下实现了一维传导，而无需模式混合。 (iii)还研究了“单线”晶体管的晶体管特性。 I .5μm栅极晶体管在300K和77K时的跨导分别为580mS/mm和650mS/mm。这些结果属于基于 GaAs/AlGaAs 的调制掺杂晶体管的高端。这一结果表明高质量一维电子系统的成功制造。它还显示出极小的栅极漏电流，约为数十皮安。加上这种低泄漏特性，目前的量子线方法被证明具有基于经典和量子函数原理的集成量子齐尔晶体管电路的巨大潜力。较少的

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