Lignin Hydrogels as a Use Case for a New Miniaturized Chemical Sensing Platform Based on Suspended Gate Field Effect Transistors

• Published in: Advanced Sensor Research 2024-10, Vol.3 (10), p.n/a
• Main Authors: Stapf, Marieke, Komenko, Vladislav, Nong, Johanna Phuong, Adam, Jörg, Selbmann, Franz, Kravchenko, Andrey, Bremer, Martina, Fischer, Steffen, Knobloch, Klaus, Joseph, Yvonne
• Format: Article
• Language: English
• Subjects: chemical sensing; field effect transistor; humidity sensing; kraft lignin; MEMS; sensitive materials; suspended gate FET
• ISSN: 2751-1219; 2751-1219
• DOI: 10.1002/adsr.202400040

Gas sensors based on micro‐electromechanical systems (MEMS) offer advantages such as a broad spectrum of potentially sensitive materials and analytes, easy miniaturization and integration, high sensitivity, and low costs. This paper introduces a novel MEMS sensor platform utilizing a suspended gate field effect transistor (SGFET) transducer. In this approach, the flexible gate membrane of the SGFET is coated with a sensitive material exhibiting responsive swelling behavior. For the proof of concept, kraft lignin hydrogel is chosen as a biorenewable material for humidity sensing. A precision dispensing technique is used to deposit kraft lignin hydrogel on the SGFETs. The sensor measurements yield reversible shifts in the sensor's output current of up to 9% in response to 5000 ppm water vapor. The results successfully demonstrate the feasibility of this new sensing platform. A novel MEMS sensor platform utilizing a suspended gate field effect transistor (SGFET) transducer is introduced. In this approach, the flexible gate membrane of the SGFET is coated with a sensitive material exhibiting responsive swelling behavior. For the proof of concept, kraft lignin hydrogel is chosen as a biorenewable material for humidity sensing.