Research Center for Humanoid Sensing, Zhejiang Lab, Hangzhou 311100, China.
Anhui Provincial Key Laboratory of Photonic Devices and Materials, Anhui Institute of Optics and Fine Mechanics, and Key Lab of Photovoltaic and Energy Conservation Materials, Chinese Academy of Sciences, Hefei 230031, China.
Nanoscale. 2023 Feb 2;15(5):2162-2170. doi: 10.1039/d2nr05324a.
Metal oxide semiconductor (MOS)-based chemiresistors have been widely used for detecting harmful gases in many industrial and indoor/outdoor applications, which possess the advantages of small size, low cost, integratability, and ease of use. However, power consumption has become a critical parameter for practical applications. Several methods have been explored to reduce power consumption including reducing the operation temperature, use of micro-electro-mechanical systems (MEMS), and self-heating working mode. Among them, the self-heating working mode has attracted significant attention. Herein, a facile approach of modulating bridged NW chemiresistor by Joule heating effect is proposed to combine both the superiority of single crystal nanowire (NW) carrier channels and power consumption optimization of the self-heating mode. The WO-bridged NW chemiresistors and WO film NW chemiresistors are both constructed to investigate gas responses and power consumption. Substantially magnified electrical responses (/) of WO NW chemiresistor toward NO is demonstrated by constructing a bridged structure. Under the optimal external heating condition, the responses of chemiresistors toward 5 ppm NO can be boosted from 369.7 (film NW) to 1089.7 (bridged NW). The responses to 5 ppm NO under the self-heating mode also can be boosted from 13.6 (film NW) to 24.6 (bridged NW) with a drastically declined power consumption. Self-heating bridged NWs allows for localizing the Joule heat within the nanojunction, and thus substantially lowers the power consumption to 0.13 μW (300 °C). This provides an additional opportunity for reducing power consumption of oxide chemiresistors for air quality monitoring in future.
金属氧化物半导体（MOS）基化学电阻器已广泛用于许多工业和室内/室外应用中检测有害气体，具有体积小、成本低、可集成和使用方便等优点。然而，功耗已成为实际应用的关键参数。已经探索了几种降低功耗的方法，包括降低工作温度、使用微机电系统（MEMS）和自加热工作模式。其中，自加热工作模式引起了人们的极大关注。在此，提出了一种通过焦耳加热效应调节桥接 NW 化学电阻器的简便方法，将单晶纳米线（NW）载体通道的优势和自加热模式的功耗优化结合起来。构建了 WO 桥接 NW 化学电阻器和 WO 薄膜 NW 化学电阻器来研究气体响应和功耗。通过构建桥接结构，显著放大了 WO NW 化学电阻器对 NO 的电响应（/）。在最佳外部加热条件下，化学电阻器对 5 ppm NO 的响应可以从 369.7（薄膜 NW）提高到 1089.7（桥接 NW）。在自加热模式下，化学电阻器对 5 ppm NO 的响应也可以从 13.6（薄膜 NW）提高到 24.6（桥接 NW），同时功耗大幅降低。自加热桥接 NW 允许在纳米结内局部化焦耳热，从而将功耗降低到 0.13 μW（300°C）。这为未来空气质量监测中降低氧化物化学电阻器的功耗提供了另一个机会。
