• Journal of Sensor Science and Technology
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• v.22 no.3
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• pp.207-211
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• 2013

In this research, the pH sensor was developed using CNT nanosheet with Nafion coating for the advanced medical sensor such as a blood gas analyzer. The CNT nanosheet was formed by dielectrophoresis and water-meniscus between cantilever-type electrodes. Then, the process of the heat annealing and the Nafion coating was conducted for reducing contact resistance and giving proton selectivity respectively. We measured the response of the pH sensor as the electrolyte-gated CNT-nanosheet field effect transistor. The sensor showed a linear current ratio in a similar range of the normal blood pH. A calibration method for decreasing of the response variation among sensors has also been introduced. Coefficient of variance of the pH sensor was decreased by applying the calibration method. A linear relation between the calibrated response of the sensors and pH variance was also obtained. Finally, the pH sensor with a high resolution was fabricated and we verify the feasibility of the sensor by applying the calibration method.

• Korean Journal of Materials Research
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• v.28 no.11
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• pp.627-632
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• 2018

Two dimensional(2D) crystals, composed of a single layer or a few atomic layers extracted from layered materials are attracting researchers' interest due to promising applications in the nanoelectromechanical systems. Worldwide researchers are preparing devices with suspended 2D materials to study their physical and electrical properties. However, during the fabrication process of 2D flakes on a target substrate, contamination occurs, which makes the measurement data less reliable. We propose a dry transfer method using poly-methyl methacrylate(PMMA) for the 2D flakes to transfer onto the targeted substrate. The PMMA is then removed from the device by an N-Methyl-2-pyrrolidone solution and a critical point dryer, which makes the suspended 2D flakes residue free. Our method provides a clean, reliable and controllable way of fabricating micrometer-sized suspended 2D nanosheets.