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.

本论文的总体目标是研究InAs/GaSb耦合量子威尔斯阱中的拓扑绝缘体相以及TI基器件的实现。为此，InAs/GaSb结构的生长与分子束外延将被优化。这将包括在不同衬底（GaAs和GaSb）上的生长以及通过生长条件的系统变化来优化界面配置。本计画的第二个目标是发展双面闸极InAs/GaSb量子威尔斯井的制程。基于GaSb的层结构具有在器件处理中必须注意的许多特性，例如，当氧化时形成导电表面层。因此，技术开发将包括研究表面钝化方法以及定义接触和双栅极的不同方法。除了用于基本表征的简单霍尔条之外，还将研究更复杂的几何形状，例如条纹或圆形门。这些结构利用了利用栅极电压调谐相变的可能性，因此允许实现不同相位彼此相邻的复杂景观。输运测量将用于研究InAs/GaSb样品中的剩余体电导率，不同相位之间的门致开关和环中的持续电流。该项目还将研究实现拓扑绝缘体FET的可能性，该拓扑绝缘体FET可以从正常绝缘状态切换到电流由边缘沟道承载的几乎无耗散状态。