Nano-structured RC Networks - A Pathway To Artificial Skin

纳米结构 RC 网络 - 人造皮肤的途径

• 批准号: EP/Y002172/1
• 负责人: Iddo Amit
• 金额: $ 21.1万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FY002172%2F1
• 关键词: Nano; structured; RC; Networks; Pathway

The ambitious research programme will see the development of a location sensitive touch sensor that can conform, after its fabrication, to flexible irregular surfaces and thus, can function as the sensing element in an artificial skin graft. The vision for the sensor is that its low power consumption, large area and simple device architecture will contribute to its ability to adapt to use in healthcare applications.The concept for the 'random impedance network sensors', or RINS, stems from the morphology of artificially synthesised atomically thin materials, that are grown almost exclusively as polycrystalline. Polycrystallinity in semiconductors is usually avoided in high-end applications because i) their resistivity is higher than their monocrystalline (MC) equivalents, and ii) each pair of crystallites (or grains) is separated by an amorphous and defect-rich interface (grain boundary) which is an additional source of resistivity. The few exceptions to the rule, such as degenerately doped polycrystalline (PC) silicon, which is used as gate metal in MOSFETs, or PC-Si photovoltaic cells marketed at the low-end of consumer-grade products, highlight the marginal position PC materials occupy in the global microelectronics industry. The first hypothesis is that PC thin films are inherently depleted of free charge carriers due to dielectric mismatch with their environment. Fewer charge carriers mean that the electrostatic screening efficiency is diminished and is manifested in extraordinarily long screening lengths and wide capture cross sections. This translates to a long-distance sensitivity to electrostatic events, such as the touch of a finger. The second hypothesis is that the intricate network of grains and grain boundaries forms a randomly oriented network of resistors (grains) and voltage-controlled capacitors (boundaries), which display both DC resistance and AC reactance. The resulting film impedance is bias-dependent, non-linear, and, crucially, position dependent, as each current pathway along the material carries a signature impedance characteristic. The combination of these hypotheses enables positioning of any electrostatic event, such as a finger touch, by triangulation of its position on the surface, making PC thin films the ideal substrates for position sensitive applications.To realise this new paradigm in location sensitive touch sensing, the full electronic structure of the grain-grain boundary system needs to be known, and the transport mechanism of traversing charge carriers across it needs to be well understood. The research methodology will include a combination of functional probe microscopy with macroscopic transport measurements, which will inform the design of the RINS detector. Finally, we aim to develop the sensor itself, and design the methodology by which electrostatic 'events' on its surface are mapped to their exact location using the reading from few low power peripheral probes.The stark difference between the proposed sensing mechanism and the sensors available today translate to exciting opportunities for new applications. Currently, capacitive touch sensors, such as those used in mobile phones and tablet devices, consist of orthogonal grid of transparent electrodes made of rare earth materials. This limits their use to applications on rigid surfaces, or surfaces that are flexible on a large, pre-defined radius of curvature. The sensor proposed here overcomes this limitations by using only peripheral electrodes, alleviating the need of rigid grid patterning. Furthermore, in current sensors location is inferred through capacitive changes at an overlap node between two orthogonal electrodes, and their nearby nodes. This means that nodes need to be sequentially addressed and read, making the response time long, especially on large surfaces. The use of few peripheral probes, all continuously read, means that processing the information can be done quickly, and on a much larger scale.

雄心勃勃的研究计划将看到一个位置敏感的触摸传感器的开发，该触摸传感器可以在制造后符合柔性不规则表面，因此可以充当人造皮肤移植物中的传感元素。传感器的愿景是，其低功耗，大面积和简单的设备体系结构将有助于适应其在医疗保健应用中的能力。“随机阻抗网络传感器”或RIN的概念源于人为合成的原子化材料的形态，这些材料几乎专用于多晶。在高端应用中通常避免使用半导体中的多晶基元，因为i）它们的电阻率高于其单晶（MC）等效物，ii）每对Crystallites（或晶粒）都被无定形和缺陷的富含缺陷且富含缺陷的界面（晶界）隔开，这是另一个电阻率的源。该规则的少数例外，例如掺杂的多晶（PC）硅，该硅被用作MOSFET中的栅极金属，或以消费级产品低端销售的PC-SI光伏电池，突出显示了全球微电子产业中的边际位置PC PC PC PC PC PC PC材料。第一个假设是，由于与环境的介电不匹配，PC薄膜固有地耗尽了自由电荷载体。较少的电荷载体意味着静电筛选效率降低，并以非常长的筛选长度和宽阔的捕获横截面表现出来。这转化为对静电事件的长距离敏感性，例如手指的触摸。第二个假设是，复杂的晶粒和晶界网络形成了一个随机定向的电阻网络（晶粒）和电压控制的电容器（边界），这些网络既显示直流电阻和交流电抗。所得的膜阻抗是偏置依赖性，非线性和至关重要的位置依赖性的，因为沿材料的每个电流途径具有签名阻抗特征。这些假设的组合可以通过将其在表面上的位置进行三角测量，使PC薄膜成为位置敏感应用的理想基础，从而实现任何静电事件的定位，例如手指触摸。实现位置敏感的触摸感中的这种新范式，谷物粒度边界系统的完整电子结构需要众所周知，需要众所周知的运输机构，并且需要跨越的运输机构。研究方法将包括功能探针显微镜与宏观运输测量的组合，这将为RINS检测器的设计提供信息。最后，我们旨在开发传感器本身，并设计使用静电“事件”在其表面上映射到其确切位置的方法，该方法使用了几个低功率的外围探针的读数。拟议的传感机制与今天可用的传感器之间的明显差异转化为令人兴奋的新应用的激动人心的机会。当前，电容式触摸传感器，例如在手机和平​​板电脑设备中使用的触摸传感器，由稀有材料制成的透明电极的正交网格组成。这将它们用于在刚性表面或在大型预定义的曲率半径上柔韧的表面上的应用。这里提出的传感器通过仅使用外围电极来克服这种局限性，从而减轻了刚性网格模式的需求。此外，在当前传感器中，通过在两个正交电极及其附近的节点之间的重叠节点上的电容变化来推断位置。这意味着需要顺序解决和读取节点，使响应时间很长，尤其是在大表面上。几乎不断读取的几个外围探针的使用意味着可以在更大的规模上快速完成信息。