Effect of Surface Modification on the Fundamental Electrical Characteristics of Solution-Gated Indium Tin Oxide-Based Thin-Film Transistor Fabricated by One-Step Sputtering
Effect of Surface Modification on the Fundamental Electrical Characteristics of Solution-Gated Indium Tin Oxide-Based Thin-Film Transistor Fabricated by One-Step Sputtering
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DOI：
10.1021/acs.langmuir.2c03225
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发表时间：
2023-03-28
期刊：
影响因子：
3.9
通讯作者：
Sakata，Toshiya
中科院分区：
文献类型：
--
作者：
Katayama，Ritsu;Sakata，Toshiya
我们的溶液门控氧化铟锡（ITO）基薄膜晶体管（TFT）通过单步溅射生产，在生物电子领域具有巨大的未来潜力。特别是，ITO通道表面的化学修饰预计将有助于生物分子识别，由于一个非常陡峭的亚阈值斜率（SS）的灵敏度。在这项研究中，我们调查的化学修饰的适体作为受体分子在ITO通道表面上的溶液门控TFT的电特性的影响。在这种情况下，SARS-CoV-2适体使用间隔分子固定在芳基重氮单层上，该芳基重氮单层用自由基清除剂电化学沉积。该单分子层不仅可以钝化ITO沟道表面，而且由于芳基重氮盐的还原反应，可以改变ITO沟道中的电子密度。事实上，芳基重氮盐的电化学沉积降低了通过ITO沟道表面的漏电流，并由于耗尽层电容的降低而提供了接近300 K热极限的陡峭SS。在适体固定化之后，漏电流和SS出乎意料地返回到接近它们在表面修饰之前的原始值。这一发现表明，适体分子应谨慎使用，因为它们的负电荷会吸引检测界面周围的阳离子。最终，由于成功的表面修饰，具有SARS-CoV-2适体的溶液门控ITO基TFT清楚地响应于灭活的SARS-CoV-2颗粒。
Our solution-gated indium tin oxide (ITO)-based thin-film transistor (TFT) produced by single-step sputtering has great future potential in bioelectronics. In particular, chemical modifications of the ITO channel surface are expected to contribute to biomolecular recognition with ultrahigh sensitivity owing to a remarkably steep subthreshold slope (SS). In this study, we investigate the effect of a chemical modification of an aptamer as a receptor molecule at the ITO channel surface on the electrical characteristics of the solution-gated TFT. In this case, a SARS-CoV-2 aptamer is immobilized using a spacer molecule on an aryl diazonium monolayer that is electrochemically deposited with a radical scavenger. The monolayer is expected to not only passivate the ITO channel surface but also change the electron density in the ITO channel owing to the reduction reaction of aryl diazonium salts. Indeed, the electrochemical deposition of aryl diazonium salts decreases the leakage current through the ITO channel surface and provides a steep SS, which is near the thermal limit at 300 K, owing to the decrease in depletion layer capacitance. After the aptamer immobilization, the leakage current and SS unexpectedly return close to their original values before the surface modifications. This finding indicates that aptamer molecules should be carefully used because their negative charges would attract cations around the detection interface. Eventually, the solution-gated ITO-based TFT with the SARS-CoV-2 aptamer clearly responds to inactivated SARS-CoV-2 particles owing to the successful surface modification.