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Carbon nanotube field-effect transistor based pH sensors

Field-effect transistor (FET) biosensor has received widespread attention due to their unique high-sensitivity properties. In conventional FET biosensors, the complicated interaction between the sample solution and the semiconductor channel always results in poor stability. Especially for FET-based...

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Bibliographic Details
Published in:Carbon (New York) 2023-03, Vol.205, p.540-545
Main Authors: Wang, Kemin, Liu, Xiaofeng, Zhao, Zijun, Li, Luyao, Tong, Jiajun, Shang, Qian, Liu, Yiwei, Zhang, Zhiyong
Format: Article
Language:English
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Summary:Field-effect transistor (FET) biosensor has received widespread attention due to their unique high-sensitivity properties. In conventional FET biosensors, the complicated interaction between the sample solution and the semiconductor channel always results in poor stability. Especially for FET-based pH sensors, the interface failure caused by the harsh acid-base working environment makes accurate, continuous, and low hysteresis pH measurement quite challenging. Here, we report a carbon nanotube (CNT)-FET pH sensor with enhanced environmental stability by introducing HfO2 film into the gate insulator. The proposed devices show desired immunity to environmental interference including various chemical and physical factors. More importantly, we verified the feasibility of this CNT-FET device for continuous pH sensing, which demonstrates a sensitivity of 67.62 mV/pH, a wide pH range of 1.34–12.68, and low hysteresis of 500 pA with pH switching loops of 4.22–10.24. This work not only realizes a high-performance pH sensor but also paves the way for the development of FET biosensors with high environmental stability, which is of great significance for FET biosensors to maintain normal working performance in complex systems. [Display omitted] •A floating gate CNT-FET biosensor with high environmental stability was fabricated and demonstrated as a high-precision pH sensor.•Excellent pH sensing capabilities were achieved, including a pH range of 1.34–12.68, sensitivity near the Nernst limit.•Based on the stable HfO2-solution interface, the desired hysteresis, and repeatability of this pH sensor were achieved.
ISSN:0008-6223
1873-3891
DOI:10.1016/j.carbon.2023.01.049