2D Arrays of Quantum Well Hall Effect Sensors for Picotesla Magnetometry of Inorganic and Organic Materials.

用于无机和有机材料皮特斯拉磁力测量的二维量子阱霍尔效应传感器阵列。

• 批准号: 2323635
• 金额: --
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2323635
• 关键词: 2D; Arrays; Quantum; Well; Hall

The principle aim of my PhD project is investigating whether Quantum Well Hall Effect (QWHE) sensors can have their dynamic range extended into the pico-tesla range. Current technologies and techniques allow the QWHE sensors, developed at the University of Manchester, to reach the very low nano-tesla range. There is a wealth of applications in pico-tesla magnetometry such as; Magneto cardiograms, Archaeology, Geophysical surveying, Body-position tracking, and many more. Currently all these applications are done using other sensors (all bulky and power hungy). If my project is successful, then QWHE sensors will be usable in this diverse range of applications leading to improvements in their respective systems as QWHE sensors are: light, small, linear over a large range, more sensitive, and low power when compared to other sensors. This could, therefore, lead to improved performance in these different and important fields. The main limitation on the lower end of the dynamic range is electronic noise. For QWHE sensors this comes in the form of flicker noise, thermal noise, shot noise, and generation-recombination noise. There are numerous techniques that can circumnavigate noise such as superheterodyne mixing which works by shifting the measuring frequency out of the realms of flicker noise. However, this project seeks to find another method that can be done before super-heterodyne mixing. The question this project asks is, 'can the sensor performance be improved by parallel connections of QWHE sensors?' This will create an array of sensors that behave as one with a lower limit on its dynamic range. This relies on a very simple part of physics, parallel connections. Connecting components in parallel usually causes their resistance to decrease by a factor of 1/N, where N is the number of sensors.The question this project then asks is 'Does this apply to the QWHE sensors?' and 'What effect does this have on the measurements?'. The theory then is simple, if the resistance goes down by a factor of 1/N then the overall noise should decrease, as all 4 types of noise previously mentioned are affected by the resistance. The objectives to achieve this are as follows. Create a small test circuit of a 2x2 array (4 sensors) and see if the phenomena can be observed. Extend the test circuit to a larger array. See if the phenomena hold true for larger arrays. Move the array from the PCB scale to the crystalline level (will allow several thousand sensors to be paralleled together). Apply superheterodyne mixing and other noise reduction techniques to the arrays to further reduce noise and enter the pico-tesla range. Find the balance between power demands/dynamic range/sensitivity that creates a useable device for implementation in pico-tesla magnetometry. The next question is why is this novel? Why can this only be done with QWHE effect sensors? This is mostly due to size and power requirements, sensors such as fluxgates are very large, and it difficult, if not impossible, to array very many. There are sources where groups have used arrays of GMRs in a similar fashion to what this project suggests but they only demonstrate N values up to a couple of hundred, before size and power requirements become prohibitive. QWHE sensors being novel in of themselves are, unlike other sensors, semiconductor devices. This means they boast very small die size (approximately 200 microns by 200 microns with sensing area as low as 5 microns x 5 microns), very low power requirements (milliwatts). QWHE technology therefore lends itself well to the concept of large number arraying.In conclusion the inherent properties of QWHE sensors lend themselves to large scale parallel arraying, which will greatly reduce their electronic noise. This should increase the dynamic range of the sensors into the pico-tesla range. The PhD intends to investigate these phenomena.

我的博士项目的主要目标是研究量子阱霍尔效应（QWHE）传感器是否可以将其动态范围扩展到皮特斯拉范围。目前的技术和技术允许曼彻斯特大学开发的QWHE传感器达到非常低的纳米特斯拉范围。在微微特斯拉磁力测量中有大量的应用，例如;磁心动图，考古学，地球物理测量，身体位置跟踪等等。目前，所有这些应用都是使用其他传感器完成的（都是笨重和耗电的）。如果我的项目成功，那么QWHE传感器将可用于各种应用，从而改进各自的系统，因为QWHE传感器与其他传感器相比：重量轻，体积小，在大范围内线性，更灵敏，功耗低。因此，这可能导致在这些不同和重要领域的业绩改善。动态范围下限的主要限制是电子噪声。对于QWHE传感器，这以闪烁噪声、热噪声、散粒噪声和生成复合噪声的形式出现。有许多技术可以绕过噪声，如超外差混频，其工作原理是将测量频率移出闪烁噪声的范围。然而，这个项目试图找到另一种方法，可以在超外差混频之前完成。该项目提出的问题是，“QWHE传感器的并联连接是否可以提高传感器性能？”“这将创建一个传感器阵列，其行为就像一个具有较低动态范围限制的传感器。这依赖于一个非常简单的物理部分，并行连接。并联元件通常会使它们的电阻降低1/N，其中N是传感器的数量。这个项目提出的问题是“这是否适用于QWHE传感器？和“这对测量有什么影响？'.理论很简单，如果电阻下降1/N，那么总噪声应该会降低，因为前面提到的所有4种噪声都会受到电阻的影响。实现这一目标的目标如下。创建一个2x2阵列（4个传感器）的小型测试电路，看看是否可以观察到这些现象。将测试电路扩展到更大的阵列。看看这种现象是否适用于更大的数组。将阵列从PCB规模移动到晶体水平（将允许数千个传感器集成在一起）。 将超外差混频和其他降噪技术应用于阵列，以进一步降低噪声并进入皮特斯拉范围。找到功率需求/动态范围/灵敏度之间的平衡，从而创建用于皮特斯拉磁力测量的可用设备。下一个问题是，为什么是这部小说？为什么只有QWHE效应传感器才能做到这一点？这主要是由于尺寸和功率的要求，传感器，如磁通门是非常大的，它很难，如果不是不可能的，阵列非常多。有消息来源称，一些团体以与本项目建议的类似方式使用GMR阵列，但在尺寸和功耗要求变得过高之前，它们只展示了高达几百个的N值。与其他传感器不同，QWHE传感器本身是新颖的半导体器件。这意味着它们拥有非常小的芯片尺寸（大约200微米× 200微米，传感面积低至5微米× 5微米），非常低的功耗要求（毫瓦）。因此，QWHE技术非常适合于大数量阵列的概念。总之，QWHE传感器的固有特性适合于大规模并行阵列，这将大大降低它们的电子噪声。这应该会将传感器的动态范围增加到皮特斯拉范围。博士打算研究这些现象。