InAs/GaSb/AlSB 2D topological insulator materials and devices

InAs/GaSb/AlSB 二维拓扑绝缘体材料与器件

• 批准号: 237739083
• 负责人: Professor Dr. Martin Kamp
• 金额: --
• 依托单位: Lehrstuhl für Technische Physik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/237739083?language=en
• 关键词: InAs; GaSb; AlSB; 2D; topological

The overall objective of this proposal is the investigation of the topological insulator phase in InAs/GaSb coupled quantum wells and the realization of TI based devices. To this end, the growth of InAs/GaSb structures with molecular beam epitaxy will be optimized. This will include growth on different substrates (GaAs and GaSb) and the optimization of the interface configuration by a systematic variation of the growth conditions. The second objective of the proposal is the development of a fabrication processes for double-side gated InAs/GaSb quantum wells. GaSb based layer structures have a number of peculiarities that have to be taken care of in device processing, e.g. the formation of conductive surface layers when oxidized. The technology development will therefore include the study of passivation methods for the surface and different approaches for the definition of the contacts and double gates. Besides simple Hall-bars for basic characterization, more complex geometries such as stripes or circular gates will be investigated. These structures make use of the possibility to tune the phase transition with the gate voltage, and therefore allow the realization of complex landscapes where different phases are located next to each other. Transport measurements will be used to study the residual bulk conductivity in InAs/GaSb samples, gate induced switching between different phases and persistent currents in rings. The project will also investigate the possibility to realize of topological insulator FET which can be switched from a normal insulating state to a nearly dissipationless state where the current is carried by the edge channels.

该提案的总体目的是研究INAS/GASB耦合量子孔中拓扑绝缘体阶段以及基于TI的设备的实现。为此，将优化具有分子束外延的INAS/GASB结构的生长。这将包括对不同底物（GAAS和GAS）的生长以及通过系统变化的生长条件来优化界面构型。该提案的第二个目标是开发双面门控INAS/GASB量子井的制造过程。基于煤气的层结构具有许多在设备处理中必须照顾的特殊性，例如氧化后导电表面层的形成。因此，技术开发将包括研究表面的钝化方法以及用于定义接触和双门的不同方法。除了简单的霍尔栏以进行基本特征外，还将研究更复杂的几何形状，例如条纹或圆形大门。这些结构利用了与栅极电压调整相变的可能性，因此允许实现复杂的景观，其中不同的相位位于彼此相邻的地方。运输测量将用于研究INAS/GASB样品中的残余电导率，栅极诱导不同相之间的切换和环中的持续电流。该项目还将调查实现拓扑绝缘子FET的可能性，拓扑绝缘子FET可以从正常的绝缘状态转到边缘通道携带电流的几乎无耗散状态。