ULTRA-HIGH-RESOLUTION, ULTRA-SENSITIVE MULTIFUNCTIONAL BALLISTIC NANO SENSORS FOR THE SIMULTANEOUS DETECTION OF MAGNETIC, ELECTRIC AND OPTICAL FIELDS

用于同时检测磁场、电场和光学场的超高分辨率、超灵敏多功能弹道纳米传感器

• 批准号: EP/J014699/1
• 负责人: Lesley Cohen
• 金额: $ 62.85万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FJ014699%2F1
• 关键词: ULTRA; RESOLUTION; SENSITIVE; MULTIFUNCTIONAL; BALLISTIC

At macroscopic length scales, charge carriers in semiconductors can be described by diffusive transport properties and sensor concepts such as the Hall Effect are applicable. When materials are fabricated at the nanoscale, new properties emerge and quantum effects dominate. In high-mobility materials such as narrow-gap semiconductors (NGS), charge carriers exhibit ballistic properties, when device length scales are smaller than the electron mean free path. In InSb (and InAs) quantum well structures, room-temperature mobilities exceed 40,000 (and 25,000) cm2/Vs, respectively, yielding electron mean free paths in excess of 500nm, which are accessible in principle using current processing technology. Nevertheless, room-temperature ballistic effects, even in high mobility NGS have remained elusive. As a result there has been no significant exploration and exploitation of this interesting and potentially important transport regime. As a result of current funding (EPSRC EP/F067216 - EP/F065922 - end date November 2011) we have made significant theoretical and experimental developments, resulting in the demonstration of room temperature ballistic effects in NGS heterostructures. We have shown that it is possible to create collimated ballistic electrons in a simple cross-structure, which enhances the so called negative bend resistance (NBR). We have also shown that collimated NBR sensor responsivity (the change in four terminal device resistance to the perturbing field) scales with inverse device size. Remarkably, this means that there is no significant loss in sensor performance as the dimensions shrink, a highly desirable property for nanoscale electronics applications.The focus of our new proposal is to build on these considerable experimental and theoretical developments. We plan to use the NBR geometry as a natural platform to realise high sensitivity multifunctional NGS ballistic nanosensors operating at room temperature, which utilise the change in electrical resistance that results when the device is exposed to magnetic, electric and/or optical fields. As part of this vision we plan to integrate two other key device concepts that will enable the multifunctional character of the devices and boost sensitivity. The first is our discovery that in the appropriate device geometry, perturbing external fields, such as optical fields, can convert carriers from the ballistic to the diffusive regime. The second is that a metal shunt appropriately placed within the device architecture, provides a low resistance path and access to that path via a Schottky barrier is tunable via external perturbing fields. This latter property has been used to great effect in diffusive devices known as EXX sensors, which were invented by a coinvestigator and visiting academic on our proposal, Prof Stuart Solin. Apart from our own preliminary investigations, the integration of a metallic shunt in the ballistic limit, is a completely new concept and aspects such as plasmonic effects and hot carrier effects will need to be investigated. Up to this time our achievements are based on InSb heterostructures. The motivation to examine the smallest possible devices, means that the grant activities will include exploration of the properties of InAs quantum well devices. InAs offers similar room temperature mean free paths to InSb, but has attractions including lower overall resistance, the option to be more heavily doped and greater potential for tunability as far as controlling collimation because of negligible side wall depletion.The study of interface effects in the ballistic regime at room temperature is a field almost completely unexplored and because of the recognised demand for high-resolution high-sensitivity sensors for applications spanning biosensing, point of care diagnostics using magnetic bead detection, ICT, and Security, our work is timely and fits well within the EPSRC research strategic areas.

在宏观长度尺度上，半导体中的电荷载流子可以通过扩散传输特性来描述，并且适用霍尔效应等传感器概念。当材料在纳米尺度上制造时，新的特性就会出现，并且量子效应占主导地位。在窄带隙半导体 (NGS) 等高迁移率材料中，当器件长度尺度小于电子平均自由程时，电荷载流子表现出弹道特性。在InSb（和InAs）量子阱结构中，室温迁移率分别超过40,000（和25,000）cm2/Vs，产生超过500nm的电子平均自由程，原则上使用当前处理技术即可实现。然而，即使在高迁移率 NGS 中，室温弹道效应仍然难以捉摸。因此，尚未对这一有趣且具有潜在重要意义的运输体系进行重大探索和利用。由于当前的资助（EPSRC EP/F067216 - EP/F065922 - 结束日期 2011 年 11 月），我们取得了重大的理论和实验进展，从而证明了 NGS 异质结构中的室温弹道效应。我们已经证明，可以在简单的交叉结构中产生准直弹道电子，从而增强所谓的负弯曲阻力（NBR）。我们还表明，准直 NBR 传感器响应度（四端子器件电阻对扰动场的变化）与器件尺寸成反比。值得注意的是，这意味着随着尺寸的缩小，传感器性能不会出现显着损失，这对于纳米级电子应用来说是非常理想的特性。我们新提案的重点是建立在这些大量实验和理论发展的基础上。我们计划使用 NBR 几何形状作为自然平台来实现在室温下运行的高灵敏度多功能 NGS 弹道纳米传感器，该传感器利用设备暴露于磁场、电场和/或光场时产生的电阻变化。作为这一愿景的一部分，我们计划集成另外两个关键设备概念，以实现设备的多功能特性并提高灵敏度。首先是我们的发现，在适当的器件几何形状中，扰动外部场（例如光场）可以将载流子从弹道状态转换为扩散状态。第二个是，适当放置在器件架构内的金属分流器提供低电阻路径，并且通过肖特基势垒访问该路径可通过外部扰动场进行调节。后一种特性已在被称为 EXX 传感器的扩散装置中发挥了巨大作用，该装置是由一位共同研究员兼客座学者 Stuart Solin 教授根据我们的提案发明的。除了我们自己的初步研究之外，在弹道极限中集成金属分流器是一个全新的概念，需要研究等离子体效应和热载流子效应等方面。到目前为止，我们的成就都是基于 InSb 异质结构。研究最小可能器件的动机意味着资助活动将包括探索 InAs 量子阱器件的特性。 InAs 提供与 InSb 类似的室温平均自由程，但具有较低的总电阻、可以选择更重掺杂以及由于侧壁损耗可忽略不计而在控制准直方面具有更大的可调潜力。室温下的弹道状态是一个几乎完全未被探索的领域，因为人们认识到生物传感、使用磁珠检测的护理点诊断、ICT 和应用领域对高分辨率高灵敏度传感器的需求。安全性方面，我们的工作非常及时，并且非常适合 EPSRC 的研究战略领域。

项目成果

Magnetic topological lithography: Gateway to the artificial spin ice manifold

磁拓扑光刻：人造自旋冰流形的门户

• DOI: 10.48550/arxiv.1704.07439
• 发表时间: 2017
• 作者: Gartside J

A novel method for the injection and manipulation of magnetic charge states in nanostructures.

• DOI: 10.1038/srep32864
• 发表时间: 2016-09-12
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Gartside JC;Burn DM;Cohen LF;Branford WR
• 通讯作者: Branford WR

Multifunctional semiconductor micro-Hall devices for magnetic, electric, and photo-detection

• DOI: 10.1063/1.4936932
• 发表时间: 2015-12
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: A. Gilbertson;H. Sadeghi;V. Panchal;O. Kazakova;C. Lambert;S. Solin;L. Cohen

High resolution InSb quantum well ballistic nanosensors for room temperature applications

适用于室温应用的高分辨率 InSb 量子阱弹道纳米传感器

• DOI: 10.1063/1.4848310
• 发表时间: 2013
• 作者: Gilbertson A

Shunt-Enhanced, Lead-Driven Bifurcation of EEC Sensor Responsivity

EEC 传感器响应度的分流增强、引线驱动分叉

• DOI: 10.1109/jsen.2015.2445971
• 发表时间: 2015
• 期刊: IEEE Sensors Journal
• 影响因子: 4.3
• 作者: Werner F