Nanda Aman, Singh Vivek, Jha Ravindra Kumar, Sinha Jyoti, Avasthi Sushobhan, Bhat Navakanta
Centre for Nanoscience and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India.
ACS Appl Mater Interfaces. 2021 May 12;13(18):21936-21943. doi: 10.1021/acsami.1c01085. Epub 2021 Apr 29.
CuO is a multifunctional metal oxide excellent for chemiresistive gas sensors. In this work, we report CuO-based NO sensors fabricated chemical vapor deposition (CVD). CVD allows great control on composition, stoichiometry, impurity, roughness, and grain size of films. This endows sensors with high selectivity, responsivity, sensitivity, and repeatability, low hysteresis, and quick recovery. All these are achieved without the need of expensive and unscalable nanostructures, or heterojunctions, with a technologically mature CVD. Films deposited at very low temperatures (≤350 °C) are sensitive but slow due to traps and small grains. Films deposited at high temperatures (≥550 °C) are not hysteretic but suffer from low sensitivity and slow response due to lack of surface states. Films deposited at optimum temperatures (350-450 °C) combine the best aspects of both regimes to yield NO sensors with a response of 300 % at 5 ppm, sensitivity limit of 300 ppb, hysteresis of <20%, repeatable performance, and recovery time of ∼1 min. The work demonstrates that CVD might be a more effective way to deposit oxide films for gas sensors.
氧化铜是一种用于化学电阻式气体传感器的多功能金属氧化物。在本工作中，我们报道了通过化学气相沉积（CVD）制备的基于氧化铜的一氧化氮传感器。CVD能够很好地控制薄膜的成分、化学计量比、杂质、粗糙度和晶粒尺寸。这赋予传感器高选择性、响应性、灵敏度和可重复性，低滞后性以及快速恢复能力。所有这些都是在无需昂贵且不可扩展的纳米结构或异质结的情况下，通过技术成熟的CVD实现的。在非常低的温度（≤350°C）下沉积的薄膜由于陷阱和小晶粒而敏感但响应缓慢。在高温（≥550°C）下沉积的薄膜没有滞后现象，但由于缺乏表面态而灵敏度低且响应缓慢。在最佳温度（350 - 450°C）下沉积的薄膜结合了两种情况的最佳方面，从而得到在5 ppm时响应为300%、灵敏度极限为300 ppb、滞后小于20%、性能可重复且恢复时间约为1分钟的一氧化氮传感器。这项工作表明，CVD可能是一种更有效的沉积用于气体传感器的氧化物薄膜的方法。
