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

摘要：征求提案2104142“pNUTs：用于类似尘埃的机载通信链路的压电纳米级超声换能器”超声已经发现了广泛的应用范围，从水下通信，结构部件的无损评估，指纹传感，触觉反馈，测距，实时定位系统和模拟计算。超声波换能器是超声波系统的核心部件。通过使用微机械薄膜的传感器的小型化，它在新应用领域的广泛部署成为可能。将形成换能器的薄膜进一步小型化到纳米级，可以大大提高设备的灵敏度或大幅减少面积，从而实现一系列新的深远应用，例如极小尺寸（“类似灰尘”）传感器或微型机器人网络之间的通信，以及非侵入式生物医学或神经植入物。然而，进一步的小型化带来了与薄膜合成、结构中残余应力控制和换能器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，并提供一种新型的设备，称为压电纳米级超声换能器（pNUTs）。为了尽量减少传播损耗，pNUTs工作频率在40khz和100khz之间。在这个频率范围内工作的纳米级换能器面临着对残余应力和与空气相互作用的高灵敏度的挑战，这往往会使结构变得僵硬，并且使精确设置器件谐振频率变得极其困难。考虑到这些限制，研究的重点是合成具有可控应力的氮化铝纳米级压电薄膜（薄至10纳米），并将其排列成新颖的pNUT几何形状。还研究了pNUTs阵列，以便在给定的形状因素下实现数量级的灵敏度改进。pNUTs的现场使用将通过唤醒接收器机载通信链路的板级实现来演示。这些演示将告诉研究人员pNUTs的最终灵敏度、范围和调制速度。“这个奖项反映了国家科学基金会的法定使命，并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，被认为值得支持。

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.