pNUTs: Piezoelectric Nanoscale Ultrasonic Transducers for Dust-Like Airborne Communication Links

AbstractUnsolicited Proposal 2104142“pNUTs：Piezoelectric Nanoscale Ultrasonic Transducers for Dust-Like Airborne Communication Links“超声已经发现了广泛的应用，从水下通信、结构部件的无损评估和指纹传感，到触觉反馈、测距、实时定位系统和模拟计算。超声换能器是超声系统的核心部件。它的广泛部署的一个新的应用领域是可能的微型化的传感器使用微机械薄膜。将形成换能器的膜进一步小型化到纳米级可以产生装置灵敏度的实质性改进或面积的显著减小，因此能够实现新的一组深远的应用，例如极小形状因子（“灰尘状”）传感器或微型机器人和非侵入式生物医学或神经植入物的网络之间的通信。然而，进一步的小型化带来了与膜的合成、结构中残余应力的控制以及换能器的机电设计相关的基本挑战。该项目计划解决这些基本的缩放挑战，并提供一类新的设备，称为压电纳米级超声换能器（pNUTs）。为了最小化传播损耗，pNUT在40 kHz和100 kHz之间的频率下工作。纳米级传感器在该频率范围内的操作受到对残余应力和与空气相互作用的高敏感性的挑战，这往往会破坏结构并使得精确设置器件谐振频率变得非常困难。考虑到这些限制，研究工作的重点是合成纳米级的氮化铝压电薄膜（薄至10 nm）与可控的应力，并安排在一个新的pNUT的几何形状。还研究了pNUTs阵列，以便对于给定的形状因子实现灵敏度的数量级改进。pNUT的现场使用将通过唤醒接收器机载通信链路的板级实施来演示。这些演示将告知研究人员pNUT能够实现的最终灵敏度，范围和调制速度。“这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

AbstractUnsolicited Proposal 2104142“pNUTs: Piezoelectric Nanoscale Ultrasonic Transducers for Dust-Like Airborne Communication Links”Ultrasound has found a broad range of applications spanning from underwater communication, nondestructive evaluation of structural components, and fingerprint sensing, to haptics feedback, ranging, real-time locating systems and analog computing. The ultrasonic transducer is the core component behind an ultrasound system. Its wide deployment for a new realm of applications was made possible by the miniaturization of the transducer using micromachined thin films. Further miniaturization of the films forming the transducer to the nanoscale could yield substantial improvements in device sensitivity or dramatic reduction in area, hence enabling a new set of far reaching applications such as communication amongst networks of extremely small form factor (“dust-like”) sensors or microrobots and non-intrusive biomedical or neural implants. However, further miniaturization comes with fundamental challenges associated with the synthesis of the films, the control of residual stresses in the structure, and the electromechanical design of the transducer. This project plans to tackle these fundamental scaling challenges and deliver a new class of devices labeled as piezoelectric nanoscale ultrasonic transducers (pNUTs). To minimize propagation losses, pNUTs operate at frequencies between 40 kHz and 100 kHz. Operation in this frequency range of nanoscale transducers is challenged by the high sensitivity to residual stresses and interactions with air, which tend to stiffen the structure and make it extremely hard to precisely set the device resonant frequency. Given these constraints, the research efforts are focused on synthesizing nanoscale piezoelectric films of aluminum nitride (as thin as 10 nm) with controllable stress and arranging them in a novel pNUT geometry. pNUTs arrays are also investigated in order to achieve orders of magnitude improvement in sensitivity for a given form factor. The field use of pNUTs is going to be demonstrated through board-level implementation of airborne communication links for wake-up receivers. These demonstrations will inform the researchers on the ultimate sensitivity, range and modulation speed that pNUTs are capable of. "This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.