Cai Xianfa, Xu Lizhong
School of Mechanical Engineering, Yanshan University, Qinhuangdao 066000, China.
Micromachines (Basel). 2022 Dec 16;13(12):2242. doi: 10.3390/mi13122242.
One-dimensional nanobeam mass sensors offer an unprecedented ability to measure tiny masses or even the mass of individual molecules or atoms, enabling many interesting applications in the fields of mass spectrometry and atomic physics. However, current nano-beam mass sensors suffer from poor real-time test performance and high environment requirements. This paper proposes a piezoelectrically excited ZnO nanowire (NW) mass sensor with closed-loop detection at room temperature to break this limitation. It is detected that the designed piezo-excited ZnO NW could operate at room temperature with a resonant frequency of 417.35 MHz, a quality factor of 3010, a mass sensitivity of -8.1 Hz/zg, and a resolution of 192 zg. The multi-field coupling dynamic model of ZnO NW mass sensor under piezoelectric excitation was established and solved. The nonlinear amplitude-frequency characteristic formula, frequency formula, modal function, sensitivity curve, and linear operating interval were obtained. The ZnO NW mass sensor was fabricated by a top-down method and its response to ethanol gas molecules was tested at room temperature. Experiments show that the sensor has high sensitivity, good closed-loop tracking performance, and high linearity, which provides great potential for the detection of biochemical reaction process of biological particles based on mechanics.
一维纳米梁质量传感器提供了前所未有的能力来测量微小质量，甚至单个分子或原子的质量，从而在质谱分析和原子物理领域实现了许多有趣的应用。然而，目前的纳米梁质量传感器存在实时测试性能差和环境要求高的问题。本文提出了一种在室温下具有闭环检测功能的压电激发氧化锌纳米线（NW）质量传感器，以突破这一限制。经检测，所设计的压电激发氧化锌纳米线在室温下工作，共振频率为417.35兆赫兹，品质因数为3010，质量灵敏度为-8.1赫兹/皮克，分辨率为192皮克。建立并求解了压电激发下氧化锌纳米线质量传感器的多场耦合动力学模型。得到了非线性幅频特性公式、频率公式、模态函数、灵敏度曲线和线性工作区间。采用自上而下的方法制备了氧化锌纳米线质量传感器，并在室温下测试了其对乙醇气体分子的响应。实验表明，该传感器具有高灵敏度、良好的闭环跟踪性能和高线性度，为基于力学的生物颗粒生化反应过程检测提供了巨大潜力。
