Lim Namsoo, Kim Hyeonghun, Pak Yusin, Byun Young Tae
Sensor System Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.
School of Engineering Technology, Purdue University, West Lafayette, IN 47907, USA.
Materials (Basel). 2021 Apr 30;14(9):2347. doi: 10.3390/ma14092347.
This paper demonstrates the enhanced NO sensing performance of graphene with defects generated by rapid thermal annealing (RTA). A high temperature of RTA (300-700 °C) was applied to graphene under an argon atmosphere to form defects on sp carbon lattices. The density of defects proportionally increased with increasing the RTA temperature. Raman scattering results confirmed significant changes in sp bonding. After 700 °C RTA, I/I, I/I, and FWHM (full width at half maximum)(G) values, which are used to indirectly investigate carbon-carbon bonds' chemical and physical properties, were markedly changed compared to the pristine graphene. Further evidence of the thermally-induced defects on graphene was found via electrical resistance measurements. The electrical resistance of the RTA-treated graphene linearly increased with increasing RTA temperature. Meanwhile, the NO response of graphene sensors increased from 0 to 500 °C and reached maximum (R = 24%) at 500 °C. Then, the response rather decreased at 700 °C (R = ~14%). The results imply that rich defects formed at above a critical temperature (500 °C) may damage electrical paths of sp chains and thus deteriorate NO response. Compared to the existing functionalization process, the RTA treatment is very facile and allows precise control of the NO sensing characteristics, contributing to manufacturing commercial low-cost, high-performance, integrated sensors.
本文展示了通过快速热退火（RTA）产生缺陷的石墨烯具有增强的NO传感性能。在氩气气氛下对石墨烯施加高温RTA（300 - 700°C），以在sp碳晶格上形成缺陷。缺陷密度随RTA温度升高而呈比例增加。拉曼散射结果证实了sp键合的显著变化。在700°C RTA后，用于间接研究碳 - 碳键化学和物理性质的I/I、I/I和半高宽（FWHM）(G)值与原始石墨烯相比有明显变化。通过电阻测量发现了石墨烯上热诱导缺陷的进一步证据。RTA处理的石墨烯的电阻随RTA温度升高呈线性增加。同时，石墨烯传感器的NO响应在0至500°C范围内增加，并在500°C时达到最大值（R = 24%）。然后，在700°C时响应反而下降（R = ~14%）。结果表明，在高于临界温度（500°C）形成的丰富缺陷可能会破坏sp链的导电路径，从而降低NO响应。与现有的功能化过程相比，RTA处理非常简便，并且能够精确控制NO传感特性，有助于制造商业低成本、高性能的集成传感器。
