Mass Production\nof Carbon Nanotube Transistor Biosensors\nfor Point-of-Care Tests

Low-dimensional\nsemiconductor-based field-effect transistor (FET)\nbiosensors are promising for label-free detection of biotargets while\nfacing challenges in mass fabrication of devices and reliable reading\nof small signals. Here, we construct a reliable technology for mass\nproduction of semiconducting carbon nanotube (CNT) film and FET biosensors.\nHigh-uniformity randomly oriented CNT films were prepared through\nan improved immersion coating technique, and then, CNT FETs were fabricated\nwith coefficient of performance variations within 6% on 4-in. wafers\n(within 9% interwafer) based on an industrial standard-level process.\nThe CNT FET-based ion sensors demonstrated threshold voltage standard\ndeviations within 5.1 mV at each ion concentration, enabling direct\nreading of the concentration information based on the drain current.\nBy integrating bioprobes, we achieved detection of biosignals as low\nas 100 aM through a plug-and-play portable detection system. The reliable\ntechnology will contribute to commercial applications of CNT FET biosensors,\nespecially in point-of-care tests.